Australian Standard Classification of Drugs of Concern

The Australian Standard Classification of Drugs of Concern (ASCDC) is the Australian statistical standard for classifying data relating to drugs which are considered to be of concern in Australian society. The ASCDC is essentially a classification of type of drug of concern based on the chemical structure, mechanism of action and effect on physiological activity of the drugs of concern. The classification of Type of Drug is described as the 'main classification structure' throughout the ASCDC document. The ASCDC is intended for use in the collection, classification, storage and dissemination of all statistical, administrative and service delivery data relating to drugs of concern.

There are two additional classifications, Form of Drug and Method of Drug Use.

The ASCDC assists government planners, policy analysts and social researchers by providing a consistent framework for the classification of drug-related data. The use of the standard definitions, classifications and coding procedures detailed in the ASCDC helps to ensure the comparability and compatibility of data derived from a range of different statistical, administrative and service provision systems at both the state and national level.

The Australian Bureau of Statistics (ABS) has produced the ASCDC in line with its commitment to provide leadership in the development and promotion of statistical data standards. The provision of nationally comparable information on licit and illicit drug activity will facilitate the planning, monitoring and evaluation of strategies for the reduction of drug-related harm. These strategies were an important element of the National Drug Strategy: Australian Integrated Framework 2004-2009 (NDSF) and the ASCDC was first developed in line with the NDSF.

According to the National Drug Strategy, a framework for a coordinated, integrated response to reducing drug-related harm in Australia (p.12 NDSF), is an important element in Australia's efforts to deal with the 'drug problem'. Consequently, one of the objectives of the NDSF (p.5) is 'to develop mechanisms for the cooperative development, transfer and use of research among interested parties.'. To monitor the effectiveness of this coordinated approach, it is necessary that standard methods be adopted in the collection and classification of the data. The ASCDC is fundamental to the achievement of this aim.

To ensure that the coverage of the ASCDC is exhaustive and the framework is suitable for the classification of data, the ASCDC was reviewed in consultation with relevant Commonwealth and State government departments, academics and other experts and organisations that are significant producers or users of data on drugs of concern.

The ASCDC is an Australian statistical standard and should be used for the production and dissemination of all Australian statistics on drugs of concern. The ABS promotes the use of the ASCDC by other government agencies, private organisations, community groups and individuals. The ABS maintains and updates the ASCDC as necessary.

To define the concept of drugs of concern which underpins the classification, there are two aspects of the concept which need to be considered:

• the definition of 'drug', and
• the definition of 'concern' in relation to drugs.

There are many differing perceptions of what constitutes a drug. A precise and meaningful definition of the concept is difficult and it is not the function of this document to provide an extensive definition of the term. However, a reasonable working definition, that suits the purposes of the ASCDC, is provided in the Demand Reduction: A Glossary of Terms prepared by the United Nations International Drug Control Programme. It defines the term drug, in part, as follows:

'...In medicine, it refers to any substance with the potential to prevent or cure disease or enhance physical or mental well-being. In pharmacology, the term drug refers to any chemical agent that alters the biochemical or physiological processes of tissues or organisms...'

This definition, while including all substances which may be regarded as drugs, also includes many substances which are not considered to be 'of concern' in our society. The notion of 'concern' is implicit in the definition of drug used in the NDSF:

'A substance that produces a psychoactive effect. Within the context of the National Drug Strategic Framework, 'drug' is used generically to include tobacco, alcohol, pharmaceutical drugs and illicit drugs. The Framework also takes account of performance and image enhancing drugs and substances such as inhalants and kava.'

Results from the 2007 National Drug Strategy Household Survey conducted by the Australian Institute of Health and Welfare (AIHW) indicated that the concept of a 'drug problem' is generally associated with illicit substances such as heroin or cannabis. However, tobacco and alcohol account for the majority of drug-related illness in Australia and are also considered to be of concern.

The draft Demand Reduction: A Glossary of Terms, mentioned above, further defines the term drug as:

'A term of varied usage. In the various United Nations Conventions and in the Declaration on Drug Demand Reduction it refers to substances subject to international control...In common usage, the term often refers specifically to psychoactive drugs, and often, even more specifically, to illicit drugs. However, caffeine, tobacco, alcohol and other substances in common non-medical use are also drugs in the sense of being taken primarily for their psychoactive effects...'

From the above, it can be seen that, in its broadest sense, the term 'drug' relates to chemical substances that alter physiological processes. However, because all drugs do not have the same potential for inappropriate use, dependence or harm, drugs of concern in the ASCDC are defined as:

'Any chemical substances for which policies and programs aimed at reducing drug-related harm or reducing the availability of drugs have been developed, or which have otherwise been identified by key stakeholders in the health, welfare, and crime and justice sectors to be of current concern in the Australian context.'

This ASCDC definition naturally includes all drugs on which there are legal restrictions such as heroin and cannabis, but also includes legally obtainable drugs for which demand and harm reduction strategies are in place, such as alcohol and tobacco.

In a few instances, the ASCDC identifies drugs for which formal harm minimisation strategies are not currently in place, but which are of concern because they may, for instance, result in deleterious health outcomes if used inappropriately. Such drugs are identified because they may enhance the usefulness of the classification, particularly in the health field.

Generally, the ASCDC is designed to classify chemical substances which are of concern because they alter physiological processes to produce a psychoactive effect, to enhance performance or image, or to act as a detoxifying agent or antidote. Detoxifying agents and antidotes have been included in the ASCDC upon the request of the health sector as they are used in programs related to the reduction of drug-related harm. These drugs are of interest not only for analysis and evaluation in terms of their effectiveness in treatment programs but also because some are potentially addictive or could be used in a harmful manner.

The main classification structure of the ASCDC only identifies drugs which are regarded as being of concern on the above basis. However, as all drugs have the potential to be of concern in certain situations or contexts, the classification has been developed so that it can incorporate, at a future date, any drug that becomes recognised as a drug of concern (see Scope of the Classification, below).

The ASCDC is designed so that it can include all drugs. However, in line with the purposes of the classification, and consistent with the concept of 'drugs of concern' detailed above, the base level units of the ASCDC main structure comprise:

• selected substances identified in Schedule 8 of the Standard for the Uniform Scheduling of Drugs and Poisons, No. 13, including 'Poisons to which the restrictions recommended for drugs of dependence by the 1980 Australian Royal Commission of Inquiry into Drugs should apply'. For example, 3903 Cocaine;
• selected substances identified in Schedule 9 of the Standard for the Uniform Scheduling of Drugs and Poisons, No. 13, covering 'Poisons which are drugs of abuse, the manufacture, possession, sale or use of which should be prohibited by law except for amounts which may be necessary for medical or scientific research conducted with the approval of Commonwealth and/or State or Territory Health Authorities.' For example, 1202 Heroin;
• selected narcotic substances identified in Schedule VI of the Customs Act 1901. For example, 3103 Methamphetamine;
• selected therapeutic substances which have been identified as being subject to inappropriate use. For example, 2403 Diazepam;
• selected therapeutic substances which are used in programs intended to reduce drug-related harm or assist with detoxification. For example, 9202 Naltrexone;
• selected substances that are generally available but which have been identified as subject to inappropriate use. For example, 2101 Ethanol;
• selected substances and classes of substances prohibited by the International Olympic Committee Medical Commission. For example, 4107 Nandrolone;
• selected groups of chemically similar substances which do not support individual identification, aggregated to form useful categories as single base level units. For example, 1302 Fentanyl analogues; and
• residual (not elsewhere classified (nec)) categories of substances that are within the scope of the classification but do not support separate identification in the classification structure (see Reserved Codes for Residual Categories). For example, 1199 Organic Opiate Analgesics, nec.

If drugs or substances not currently covered by the above principles of identification are identified in the future as being of concern, they will be included in the most appropriate broad or narrow group residual category as an interim measure. They will be more appropriately classified when the next review of the classification is undertaken.

The ASCDC is designed to collect, classify and disseminate data on drugs of concern. Because most drugs have the potential to be considered of concern in certain circumstances or contexts, the scope of the classification is all drugs. However, only those drugs noted by key stakeholders in the health, welfare, and crime and justice sectors to be of current concern in the Australian context of harm minimisation are identified in the main classification structure. This includes all drugs of concern which may be identified using the criteria listed above (see Identifying the Base Level Units of the Classification, above).

It should also be noted that the main classification structure of the ASCDC does not distinguish between drugs of concern on the basis of their legality. Further, it is not a suitable vehicle for the classification of the different chemical or physical forms in which a drug may be available, and should not be used to determine the different methods of drug use. These are correlative variables for which the 'Form of Drug' and 'Method of Drug Use' classifications have been developed.

Classification criteria are the principles by which the classification categories are aggregated to form broader or higher level groupings within the classification structure. In the main classification structure of the ASCDC, these criteria are attributes, characteristics and effects of particular drugs of concern. They are used to establish how the individual drugs are related and how they can most usefully be grouped. The following classification criteria are used to determine the categories of the main classification structure:

• the similarity of drugs of concern in terms of their chemical structure and the associated mechanisms by which they produce their effects (mechanism of action); and
• the similarity of drugs of concern in terms of their effect on human physiological activity.

The most detailed level of the classification consists of separately identified drugs, aggregate groups of drugs and residual categories of drugs (see Identifying the Base Level Units of the Classification). These base level units are combined to form the narrow groups of the classification primarily on the basis of their similarity in terms of chemical structure and mechanism of action. For example, Narrow Group 24, Benzodiazepines, contains drugs that all have the same core chemical structure and a similar profile in terms of the broad mechanisms by which they produce their effects. Narrow groups formed in this manner (i.e. comprising drugs of concern that are chemically similar and similar in their mechanism of action), therefore consist of drugs that have similar broad effects on human physiological activity.

In three instances, the similarity of the broad effect of the drugs of concern on physiological activity is used as the primary classification criterion (rather than the similarity in chemical structure and their mechanism of action) when aggregating the base level units to form narrow groups. The Narrow Group 22, Anaesthetics, comprises drugs which are not similar in terms of chemical structure or broad mechanism of action but which form a useful narrow group on the basis of the similarity of their effect on physiological activity. The Narrow Group 56, Atypical Antipsychotics, comprises drugs that have different mechanisms of action but which produce a similar anti-psychotic effect. Similarly, the Narrow Group 91, Diuretics, is formed on the basis of the similarity of the effect of these drugs of concern on physiological activity. The use of the second classification criterion in this way also allows for the formation of meaningful residual categories of drugs of concern at the narrow group level.

At the first and most general level of the main classification structure, broad groups are formed by aggregating narrow groups. This aggregation of narrow groups was undertaken, as far as possible, so that the broad groups consist of narrow groups of drugs of concern which are similar in terms of their effect on physiological activity. For example, Broad Group 1, Analgesics, consists of drugs which have the effect of blocking or relieving pain.

In most cases, the primary physiological system affected by drugs in the ASCDC is the central nervous system (CNS). In instances where drugs of concern are classified on the basis of their similarity of effect on physiological activity, the nature of the effect on the CNS is usually being addressed. The most obvious exception to this principle occurs with Broad Group 4, Anabolic Agents and Selected Hormones, which contains narrow groups of drugs which are similar in terms of their effect on the endocrine system rather than the CNS.

Broad Group 6, Volatile Solvents is formed by the conventional application of the classification criteria as described above. However, the drugs included within this broad group have a similar broad physiological effect to drugs included in Broad Group 2, Sedatives and Hypnotics. Despite this similarity of physiological effect, volatile solvents have been separated from other sedatives and hypnotics.

Broad Group 9, Miscellaneous Drugs of Concern, is a residual category which contains narrow groups of drugs which do not fit into any of the other broad groups on the basis of either of the classification criteria. The two substantive narrow groups contained within this broad group do not exhibit the same broad effect on physiological activity but are considered to be of sufficient importance to warrant separate identification within the main classification structure. This broad group also contains a residual narrow group which will allow for the classification of drugs not currently identified as being of concern and which could not be classified to residual categories in any other part of the classification.

The main classification of the ASCDC has a three level hierarchical structure.

The third and most detailed level of the classification consists of the base units which are separately identified drugs of concern, aggregate groups of drugs of concern and residual categories of drugs of concern (see Identifying the Base Level Units of the Classification). The classification comprises 186 third level units including 17 aggregate groups of drugs and 36 residual 'not elsewhere classified' (nec) categories (see Reserved Codes for Residual Categories below).

The 17 third level aggregate units comprise drugs which do not support individual identification but which are aggregated to form single base level units as they are chemically similar and, when grouped, represent useful categories.

The 36 nec categories contain drugs which are not sufficiently significant, in the current Australian context, to support separate identification or representation as an aggregate base level unit. All drugs which have been identified as drugs of concern, but which are not listed separately or contained within one of the aggregate base level units, are included in the nec category of the narrow group to which they relate.

The second level of the classification consists of 38 narrow groups which contain base level units which are similar in terms of the classification criteria. Included in the 38 narrow groups are six residual 'Other' categories. These residual categories contain base level units which do not belong in any of the alternative narrow groups contained within the broad group on the basis of the classification criteria.

The first and most general level of the classification comprises eight broad groups. The broad groups are formed, in the main, by aggregating narrow groups which are broadly similar in terms of the classification criteria. The classification has one 'Miscellaneous' broad group which comprises narrow groups of drugs which were considered to be of sufficient importance to be included in the classification structure but which do not fit into any of the other seven broad groups on the basis of the classification criteria.

The theoretical and conceptual principles used to develop the main classification structure were applied in conjunction with other considerations such as: the suitability of the ASCDC for the classification of drug-related data from the health, welfare, and crime and justice sectors; the analytical usefulness of data collected within the framework; and the structural and statistical balance of the classification.

An important consideration in developing a classification for statistical purposes is that the structure be statistically balanced. The classification should not have categories at the same level in its hierarchy which are excessively disparate in their population size (the number of classifiable observations or responses each category represents in any application). This allows the classification to be used effectively for the cross-tabulation of aggregate data and for the dissemination of data from sample surveys. Strict application of this principle was not possible in the ASCDC as it was necessary to incorporate the statistical requirements of a diverse range of community activity sectors such as health, welfare, and crime and justice. As a result, not all of the categories of the classification are applicable in all collections and the categories of the classification may not represent a significant number of observations in all applications. For each individual application, the classification, while not necessarily providing an even spread of data across its whole structure, provides a framework that is useful and practical for collecting and presenting data.

One of the more notable constraints in the development of the classification was the practical requirement to represent the diverse range of available drugs of concern within a manageable classification structure. The principle adopted to achieve this end, and to serve the statistical and research purposes of the classification, was to separately identify only those drugs which are of significant concern in the Australian context.

Many of the base level drugs of concern are known by a number of proprietary (brand or trademark) names. Some potential users of the classification indicated they would prefer all these names to be represented in the classification structure for purposes of completeness. While proprietary names are often more readily recognised, it is not practical to have a list of all the known brand names of a drug as the title of each base level unit. As the categories of a classification must be mutually exclusive it is not feasible to identify each brand name as a separate category.

An additional limitation to the use of proprietary names to represent base level units is that many of the more popular or well known brand names are often used, in a generic manner, to refer to all brands of the same product. For example, Panadol to refer to paracetamol, Valium to refer to diazepam, and Prozac to refer to fluoxetine. Therefore, each drug of concern is identified once only in the classification, and where applicable, the base level units reflect the generic name of a drug. Proprietary names are included in the Coding Indexes data cube.

In some instances the generic name of a drug constituting a category of the classification is expressed as an abbreviation of the full chemical name of the psychoactive substance. This is done because of the length of the name or because the abbreviation is more commonly used than the full chemical name. Where abbreviations are used for category names in the main classification structure, the full name is provided in the List of Abbreviations and in the Coding Indexes.

A further factor which influenced the once only representation and titles of the base level units relates to the coverage of the classification. Many drugs can exist in more than one chemical form. Although most are available in their crystalline salt form (hydrochloride, sulphate, citrate, etc.), some are available in their base form. Drugs are also available in different physical forms. As the main classification structure is not intended to classify the form of a drug, substances such as cannabis, hash oil or cannabis resin are all coded to the base level unit, Cannabinoids, which represents the psychoactive compounds common to all the forms of the drug. Similarly, morphine hydrochloride, morphine sulfate and morphine tartrate are all coded to the base level unit Morphine.

Many collectors and users of data relating to drugs of concern require information on the form of a drug as well as the chemical substance. To distinguish between different forms of a particular drug a form of drug classification has been included in the ASCDC Type of Drug Classification and Additional Classifications data cube. The purpose of this classification is to act in conjunction with the main classification structure to further define data relating to drugs of concern without compromising the principles of the main classification structure. The Form of Drug classification allows users to define drugs based on the mode in which the drug exists or is encountered, for example, Powder, Leaf, Granule/rock, or Resin.

In the main classification structure, one, two and four-digit codes have been assigned to the first, second and third-level units of the classification respectively. The first digit identifies the broad group in which each narrow group and base level unit is contained. The first and second digits identify the narrow group in which each base level unit is contained. The four-digit codes represent each of the base level units which are separately identified drugs of concern, aggregate groups of drugs of concern and residual (nec) categories of drugs of concern.

For example, the one-digit code 3, denotes the third broad group in the classification structure, Stimulants and Hallucinogens. The two-digit code 31 identifies the first narrow group, Amphetamines, contained within this broad group. The four-digit code 3103 denotes the third base level unit, Methamphetamine, contained within the first narrow group, Amphetamines, of the third broad group, Stimulants and Hallucinogens.

This example is presented as follows:

31 Amphetamines

3101 Amphetamine
3102 Dexamphetamine
3103 Methamphetamine
3104 Amphetamine analogues
3199 Amphetamines, nec

It should be noted that one, two and four-digit codes ending with 9 are reserved to denote residual categories of the classification at the broad, narrow and base levels respectively (see Reserved Codes for Residual Categories below). A trailing or leading digit 0 is also reserved, for supplementary codes, which are used to process inadequately described responses in statistical collections (see Supplementary Codes below).

As the profile of drug activity in Australia changes it may be necessary to add drugs to, or delete drugs from, the classification structure. If a drug needs to be separately identified in the structure, it will be allocated the next available four-digit code in the narrow group to which it is being added. The available four-digit codes are those ending in the numerals one to eight (four-digit codes ending in zero or nine being reserved for residual categories).

The base level units identified in each narrow group in the original ASCDC were presented in alphabetical order, with the exception of the residual (nec) categories. Where new base level categories have been added to existing narrow groups in the Second Edition, they have been added following the already existing categories, disrupting the alphabetic ordering. If it is necessary to move a base level category from one narrow group to another, it will be allocated the next available code of the narrow group to which it is moved. Its previous code will not be reallocated. See the 'What's changed' section for more information.

The code scheme has been devised so that any future amendments to the structure can easily be accommodated. However, to ensure that the ASCDC remains standard, users of the classification should not make changes to the structure.

In most narrow groups of the main classification structure a four-digit code, consisting of the two digits of the narrow group followed by the digits 99, is reserved as a residual 'not elsewhere classified' (nec) base level category. All drugs which have been identified as drugs of concern but which are not separately identified in the classification structure or included in one of the aggregate base level groups, are included in the residual (nec) category of the narrow group to which they relate. Individual drugs of concern are allocated to a narrow group residual category on the following basis:

• when it is clear that the drug of concern belongs in the particular narrow group on the basis of the classification criteria; and
• when the drug of concern is a separate entity to the other identified base level units in the narrow group.

In such cases the drug of concern does not warrant separate identification in the narrow group, usually because it was statistically insignificant at the time the classification was developed or last revised.

The main classification structure has 36 residual categories at the base level.

In each broad group, codes are also reserved for residual categories at the narrow group level. These codes consist of the broad group code followed by 9. These categories are termed 'Other' and consist of separately identified drugs of concern which do not fit into any of the narrow groups contained within the broad group, on the basis of the classification criteria. The classification contains six 'Other' narrow groups. No residual narrow group is provided in Broad Group 1, Analgesics, and Broad Group 7, Cannabinoids and Related Drugs, as the narrow groups within these broad groups are logically exhaustive of all drugs within these broad groups.

The main classification structure has one residual broad group which is represented by the initial code 9. It comprises narrow groups of drugs which were considered to be of sufficient importance to be included in the classification structure but which did not fit into any of the other broad groups on the basis of the classification criteria.

It should be noted that residual categories are part of the classification structure and are to be used to classify specific drugs. They are not be be created or used to code responses which contain insufficient information to be accurately assigned to another category of the classification (see Supplementary Codes below and Coding Procedures).

Supplementary codes are used to process inadequately described responses in statistical, administrative and service delivery collections. These codes are of two types:

• four-digit codes ending with two or three zeros; and
• four-digit codes commencing with three zeros.

Codes ending in zero are described as 'not further defined' (nfd) codes and are used to code responses to a question about drugs which cannot be accurately coded to one of the base level units but which can be coded to a higher level of the classification structure.

For example, responses which contain insufficient information to be identified as relating directly to a particular drug of concern, but which are known to be within the range of drugs represented by a particular narrow group, are coded to that narrow group. Such responses are allocated an nfd code consisting of the two-digit code of the narrow group followed by 00. For instance, the response Benzodiazepine does not contain sufficient information to be coded directly to any specific drug of concern, but it can be coded to Narrow Group 24 which encompasses all Benzodiazepines. It is thus allocated the nfd code 2400, Benzodiazepines, nfd.

Similarly, responses which do not contain sufficient information to be accurately coded to a specific drug of concern, or to a narrow group, but which are known to be within the range of drugs represented by a particular broad group, are coded to that broad group. Such responses are allocated an nfd code consisting of the single-digit code of the broad group followed by 000. For example, the response Antidepressant, which does not contain sufficient information to be coded directly to any particular narrow group, can be coded to Broad Group 5 which encompasses all Antidepressants and Antipsychotics. It is thus allocated the nfd code 5000, Antidepressants and Antipsychotics, nfd.

Therefore, responses or input data which can only be assigned codes at the broad or narrow group levels of the classification can be processed within a collection at the four-digit or drug of concern level. This allows the coding process to be as precise as the input data quality allows, preserving data that would otherwise be lost and either not coded or coded as inadequately described.

Supplementary codes are listed in Table 2 of the Type of Drug Classification and Additional Classifications data cube.

Responses provided in statistical and administrative collections do not always relate directly to classification categories. A coding index is therefore necessary to act as a link between responses given and the classification, enabling responses to be assigned accurately and quickly to the appropriate category of the classification.

The ASCDC coding index for the main classification structure has been developed to assist with the implementation and use of the classification and should be used when coding applicable drug-related data. It contains a comprehensive list of the most probable drug-related responses and their correct classification codes. The index can be presented in both alphabetical and numerical (code) order.

In general, the titles of the base level categories of the classification reflects the non-proprietary or generic name for a drug. Furthermore, the base level units identify psychoactive compounds rather than the physical or chemical forms of the drugs. As many drug-related responses will not exactly match those of the classification categories, the coding index includes many proprietary or brand names, physical or chemical forms of drugs, generic substance descriptions, acronyms, chemical names and common-use or street names for drugs.

The coding index also includes a number of drugs that are not separately identified in the classification structure but which are included in the residual (nec) category of the narrow group to which they relate. In addition to its coding function, the numerical index can therefore be used to clarify the nature, extent and varietal content of each classification category.

The main classification structure coding index does not include codes for the Form of Drug or Method of Drug Use classifications. The coding index would become large and unwieldy if each entry for Type of Drug also included one or more Form of Drug or Method of Drug Use codes. Nevertheless, to facilitate the coding process, some forms of drugs are included in the coding index with the main classification structure code because the form of drug is often given as a response to a question about type of drug. For example, responses such as 'hash oil', 'heads' and 'weed' which describe a form of drug are all included in the coding index and are all coded to 7101, Cannabinoids. The codes for the categories of the Form of Drug and Method of Drug Use classifications are listed in Tables 4.1 and 4.2 of the Type of Drug Classification and Additional Classifications data cube.

When coding drug-related responses in statistical, administrative or service delivery collections, the following rules should be applied:

• responses which match exactly with an entry in the coding index are assigned the code allocated to that index entry;
• responses which have a partial match with an entry in the coding index and only differ in terms of alternative spelling, the use of abbreviations, acronyms, etc. are assigned the code allocated to that index entry;
• responses which have a partial match with an entry in the coding index and only differ in terms of qualifying or extraneous words are assigned the code allocated to that index entry; and
• responses which have a partial match with an entry in the coding index and only differ in that they refer to a different chemical form of the drug are assigned the code allocated to that index entry. For example, the response Testosterone propionate is coded to 4112 Testosterone.

As the nature of drug activity in Australia changes, (new) drugs may become prominent that are not represented in the current coding index. If responses are encountered that are not in the index, the procedures outlined below can be followed to assign codes to input data. However, to ensure that the ASCDC remains standard, the ABS should be contacted if an additional index entry is considered to be necessary and a revision to the index may be issued.

The procedures for coding new responses are:

• responses which represent proprietary or brand names are assigned the code of the psychoactive substance they contain.
  For example, if Rohypnol was a new response it would be coded to 2404 Flunitrazepam;
• responses which represent a physical form of a psychoactive substance are assigned the code of the psychoactive substance or group of substances they contain.
  For example, if Cannabis was a new response it would be coded to 7101 Cannabinoids;
• responses which represent common-use or street names are assigned the code of the psychoactive substance that is most commonly associated with the name.
  For example, if Ecstasy was a new response it would be coded to 3405 MDMA even though it is acknowledged that substances described as Ecstasy are not composed of MDMA in all instances;
• responses which represent a substance that comprises a combination of base level categories in the classification are assigned the code of the substance that is considered to be of most concern in terms of its contribution to drug-related harm.
  For example, if Rubber cement was a new response it would be coded 6201 Toluene even though it is acknowledged that this is not the only harmful compound contained within the product;
• responses which do not relate to a separately identified drug or to an aggregate group of drugs in the classification are assigned a residual 'nec' code, or a supplementary 'nfd' code (see Reserved Codes for Residual Categories and Supplementary Codes). A response should only be coded to a residual 'nec' category if it is clear that it belongs in the particular narrow group and that it contains sufficient detail to indicate that it is definitely not included in one of the other separately identified base level units. Responses which are not precise enough to be coded to any base level category should be assigned the appropriate supplementary 'nfd' code.

The additional classifications Form of Drug and Method of Drug Use are used to code responses in applications which require form of drug and method of drug use codes rather than the main classification code of the psychoactive substance. These three classifications represent different elements of drug use or different statistical variables in the context of data collection. For all these variables it is recommended that data be collected, coded and stored separately. This allows data from organisations which collect all sets of information to be compared with data from organisations which only collect information on one or two of the variables. By having the variables stored in different fields the data can be manipulated according to the needs of the organisation.

As some responses are assigned supplementary codes rather than the codes of particular drugs, it is important that in verifying input codes, manipulating data, aggregating data to higher level categories and deriving output items and tables, the full range of valid codes are included in all specifications. The valid range of codes for the main classification structure comprises the following:

• all the codes included in the detailed classification structure; and
• all the codes included in the supplementary codes list.

These codes are listed in the Type of Drug Classification and Additional Classifications data cube.

Regardless of the level of aggregation envisaged for the dissemination of statistics, the ABS recommends that data be captured, classified and stored at the four-digit level. This will allow the greatest flexibility for the output of statistics, enable more detailed and complex analysis, facilitate comparisons with data using different classifications and preserve information to provide maximum flexibility for future use of the data.

However, because of confidentiality constraints, it may not be possible to output data at the lower levels of the classification in all instances. The use of a standard classification framework will nevertheless enhance data comparability even though it may not always be possible to disseminate data at the most detailed level.

The hierarchical structure of the ASCDC allows users the flexibility to output statistics at the level of the classification which best suits their particular purposes. Data can be presented at the broad group level, narrow group level or the base level. If necessary, significant drugs within a narrow group can be presented separately while the remaining base level units within the narrow group are aggregated. The same principle can be adopted to highlight significant narrow groups within a broad group.

It should be noted that drugs from different narrow groups should not be added together to form an aggregation as this corrupts the application of the classification criteria and has repercussions on data comparability. Similarly, narrow groups from different broad groups should not be grouped together.

As noted in the Overview, the main classification structure of the ASCDC is designed to classify chemical substances which alter physiological processes. However, many collectors and users of data relating to drugs of concern require information on the physical form of a drug as well as on the chemical substance which produces the psychoactive effect. For conceptual and practical reasons, it is not appropriate to include these different elements of drug use in a single classification as this would create an overly complex classification structure.

The Form of Drug classification is intended to be used in conjunction with the main classification structure to address another aspect of information relating to drugs and to assist in creating a coherent statistical framework for the collection, storage and dissemination of data derived from a range of statistical, administrative and service provision settings. It allows data relating to drugs of concern to be further defined without compromising the principles of the main classification structure.

Form of Drug is intuitively defined by reference to the categories of the classification. For instance, the form 'Oil' is readily distinguishable from the form 'Powder' without further definition. Nevertheless, for the purposes of this classification, Form of Drug is defined as:

'The matter or material of which the drug consists and the mode in which the drug exists or is encountered.'

Form of Drug describes the outward aspect of the drug. Form of Drug does not indicate the chemical substance which alters physiological processes to produce a psychoactive effect on which the main classification structure is based, nor does it make reference to the method of drug use or the container or receptacle in which the drug is stored, transported or sold.

The Form of Drug classification was originally adapted from the Drug Form classification presented in the National Illicit Drug Statistics Framework, June 1999, a report produced by the Australian Bureau of Criminal Intelligence and the ABS for the National Community Based Approach to Drug Law Enforcement. It has been modified to include only the physical forms in which drugs are administered, exist or are encountered. It excludes the receptacles in which drugs are stored, transported or sold (e.g. vial/ampoule), with the exception of Capsule and Paper/card-tab/trip. These categories of the classification could be perceived as receptacles in which other forms of drugs are stored either as a liquid, oil or powder for a Capsule and as a liquid for a Paper/card-tab/trip. Additionally, the category Tablet could be perceived as compressed powder. As these forms of drug are generally consumed within the administering process (e.g. swallowed), and accurately describe the mode in which the drug exists or is encountered, they have been included in the classification. 'Crystalline' has not been included in the classification as 'Crystalline' can refer to either a Powder form of crystalline salts or Granule/rock form for those drugs that are a freebase or 'ice like' in appearance.

The need for and usefulness of the Form of Drug classification can be illustrated by reference to cannabis. In the Type of Drug classification structure all forms of cannabis are included in the category 7101 Cannabinoids, no distinction being made between crops of plants (whole plant), leaf and hashish. Using the Form of Drug classification it is possible to code the different forms of Cannabinoids as follows:

The category 98 Part plant-vegetable matter, may not appear to be mutually exclusive of categories 02 Leaf, 03 Flower-head, 04 Root and 05 Seed. Category 98 is used when a drug of concern is encountered (usually cannabis) that consists of or includes more than one single category of the Form of Drug classification covering the parts of a plant (i.e. 02 Leaf and 03 Flower-head). Similarly, 08 Oil has been excluded from the category 07 Liquid. Oils are a group of neutral liquids comprising three main classes: fixed (fatty) acids; mineral oils; and essential oils, of which the last two are associated with drugs of concern. 

The usefulness of the Form of Drug classification is further illustrated by reference to cocaine. Cocaine is generally sold on the street as a crystalline hydrochloride powder, but through a process called 'freebasing' crack cocaine is formed. The two forms are distinguished in the Form of Drug classification as follows:

Apart from conceptual considerations, separation of the information items (active chemical compound and form of drug) has the advantage of allowing data to be collected and used for the particular item of interest. The ABS therefore recommends that data be collected, coded, and stored for each variable separately. This allows data from organisations which collect both sets of information to be compared with data from organisations which only collect information on one of the variables. Organisations which require drug-related data further defined in terms of the form of the drug can do so by cross tabulating variables. 

The ABS therefore recommends that data be coded and stored in separate fields as follows:

Many collectors and users of statistical, administrative and service provision data relating to drugs of concern require information on the method used to administer a drug as well as data on the chemical substance which produces the psychoactive effect of the drug and on the physical form of the drug. For conceptual reasons, it is not possible to include these different elements of drug use in a single classification as this would create an overly complex classification structure.

In order to meet the need to collect and classify information relating to the method of drug use, the ABS has adopted the classification developed for use in the National Minimum Data Set for Alcohol and Other Drug Treatment Services, sponsored by the Intergovernmental Committee for Drugs. This classification was originally developed by the National Drug and Alcohol Research Centre (NDARC) and was included in the National Health Data Dictionary, Version 9 (NHDD), in association with the data element Method of Use for Principal Drug of Concern.

The Method of Drug Use classification is intended for use in conjunction with the main classification structure to address another aspect of information relating to drugs and to assist in creating a coherent statistical framework for the collection, storage and dissemination of data derived from a range of statistical, administrative and service provision settings. It allows data relating to drugs of concern to be further defined without compromising the principles of the main classification structure.

Method of Drug Use is intuitively defined by reference to the categories of the classification. For instance, the method 'Injects' is readily distinguishable from the method 'Smokes' without further definition. Nevertheless for the purposes of this classification, Method of Drug Use is defined as:

'The usual method of administering the drug of concern.'

Apart from conceptual considerations, separation of the information items (active chemical compound and method of drug use) has the advantage of allowing data to be collected and used for the particular item of interest. The ABS therefore recommends that data be collected, coded, and stored for each variable separately. This allows data from organisations which collect both sets of information to be compared with data from organisations which only collect information on one of the variables. Organisations which require drug-related data further defined in terms of the method of drug use can do so by cross tabulating variables.

The ABS therefore recommends that data be coded and stored in separate fields as follows:

The need for periodic reviews of the ASCDC to reflect the changes in the types of drugs of concern being used and the prevalence of drug usage in Australia was foreshadowed when the ASCDC was released. Feedback from key users of the ASCDC highlighted the need for a review of the ASCDC to ensure it is up to date. Accordingly the ABS undertook a review of the ASCDC in 2009.

The purpose of the review was to:

• incorporate new drugs of concern that have emerged in Australia, reflect the growth and decline of others, exclude previous drugs of concern that no longer satisfy the base level unit criteria and address any errors in the classification, and
• improve the Coding Index used to map the actual responses provided to Drugs of Concern.

There was no attempt to review the conceptual model underpinning the classification or to make major structural changes.

Extensive research was conducted to:

• confirm the appropriate terminology to be used for categories in the classification, and
• assist in assessing the accuracy of coding of drugs of concern at the broad, narrow and base levels - which was achieved primarily through consultation with users of the classifications.

The research included consultation with experts and stakeholders.

Three rounds of Stakeholder Consultation were held to determine any shortcomings with the current ASCDC and to establish which, if any, new drugs needed to be included in the classification.

To limit disruption to time series and to create as little confusion as possible, drugs separately identified in the first edition have mainly retained the same code in the Second Edition; only being allocated new codes if they have been moved to a different group. Drugs separately identified for the first time have been allocated previously unused codes. Previously used codes have not been reallocated. One effect of the decision to keep drug codes constant over time is that the original alphabetical order of drugs within narrow groups has been disrupted in some instances.

One new group has been created at the broad group level. Six new narrow groups have been included in the Second Edition, and one narrow group previously included in the first edition of the ASCDC has been removed. Four base level categories that existed in the first edition have been moved to different narrow groups. Thirty-two new base level categories have been created, and one base level category has been expanded to include a drug formerly included in a 'not elsewhere classified' category.

These changes are detailed below:

Cannabinoids and Related Drugs Broad Group

Narrow Group 32 'Cannabinoids' has been removed from Broad Group 3 'Stimulants and Hallucinogens' and a new Broad Group 7 'Cannabinoids and Related Drugs' has been created. Many users indicated that Cannabinoids did not fit well in the 'Stimulants and Hallucinogens' group. Given this, it was decided that the classification would be best served by the creation of a new broad group, Broad Group 7, 'Cannabinoids and Related Drugs' for these drugs. This new broad group will also allow for the inclusion of new base level categories for 'Cannabinoid' extracted from the plants (code 7101) and for synthesised 'Cannabinoid agonists' (7102), which stakeholders requested to have separately identified as the molecular similarity does not fit perfectly within any other base level unit.

GHB Type Drugs and Analogues

The 'GHB Type Drugs and Analogues' narrow group was created to reflect the rise in prevalence of a number of drugs that are similar to gamma-hydroxybutyrate (GHB) in action and composition that were not separately identified in the first edition of ASCDC. Stakeholder feedback indicated that use of drugs of this type is widespread enough to warrant the creation of a new narrow group. In the first edition of ASCDC, GHB type drugs were included in Narrow Group 22, 'Anaesthetics'.

Cathinones

While 'Cathinone' and 'Methcathinone' were identified as separate base level categories in the first edition of ASCDC, stakeholders identified a number of related drugs that were not separately identified. The new narrow group 'Cathinones' groups all of these drugs together. Cathinones were included in Narrow Group 39, 'Other Stimulants and Hallucinogens' in the first edition of ASCDC.

Piperazines

Narrow Group 38, 'Piperazines', represents a category of stimulant whose use as a recreational drug has increased markedly since the publication of the original ASCDC. There was considerable interest from stakeholders in having this category of drug separately identified as a narrow group. No Piperazines were separately identified in the first edition of ASCDC, although conceptually they would have been in Narrow Group 39, 'Other Stimulants and Hallucinogens'.

Atypical Antipsychotics

Narrow Group 56, 'Atypical Antipsychotics', are a class of antipsychotic medication that had only recently been introduced when the first edition of ASCDC was published. Since then, their prescription has become commonplace and the opportunity for them to be misused and abused has consequently increased. In the first edition of ASCDC, Atypical Antipsychotics were included in the nec category of Narrow Group 59, 'Other Antidepressants and Antipsychotics'.

Laxatives

Narrow Group 93 'Laxatives', comprises a type of drug that is frequently and increasingly abused, especially by people with eating disorders. The inclusion of 'Laxatives' was seen by stakeholders as a useful adjunct to the existing narrow group 'Diuretics'. Laxatives were not identified as a drug of concern in the first edition of ASCDC.

Movement of existing drugs of concern

With the creation of the new broad and narrow groups, several base level categories have been moved from existing narrow groups to these new groups. Specifically, 'Gamma-hydroxybutyrate' has moved from 2201 to 2501, 'Cannabinoids' from 3201 to 7101, 'Cathinone' from 3902 to 3701, and 'Methcathinone' from 3904 to 3702.

New drugs of concern

Due to the increasing incidence of their misuse and abuse and consequent need to individually identify them in statistics, the following base level categories have been included in the Second Edition ASCDC:

Inclusion of Psilocin with Psilocybin

Psilocybin and Psilocin are two closely related tryptamines. The two drugs are most commonly found in hallucinogenic mushrooms, and the two can exist within the same mushroom. Stakeholder feedback has indicated that in most cases, a clinician would be unable to determine if a patient was affected by psilocybin or psilocin. Therefore 'Psilocin' has been moved from 3599 'Tryptamines, nec' and combined with the first edition base level category 3505 'Psilocybin' to form a single base level category of 3505 'Psilocybin or Psilocin'.

Precursor substances

A number of stakeholders requested that the classification include a grouping for precursor substances. However, while researching the precursor substances, it became clear that this would not be possible as not all precursor substances are drugs, for example safrole (an oil used in making perfume), and some drugs, such as pseudoephedrine, would need to be included in two categories in the classification. This is not possible as all categories in a classification must be mutually exclusive.

A list of precursors can be found in the Code of Practice for Supply Diversion into Illicit Drug Manufacture published by The Plastics and Chemicals Industries Association (PACIA) on the website: http://www.pacia.org.au/Content/drugs.aspx

Comparison between ASCDC 2000 and ASCDC 2011

See the changes (including additions and deletions) in the Type of Drug Classification and Additional Classifications data cube, Table 3 Comparison of the Structure Between 2000 and 2011.

A new broad group and new narrow groups have been added to the main structure of the ASCDC.

New supplementary codes have been created for these groups where appropriate.

The following list of supplementary codes includes the new codes in bold:

This release previously used catalogue number 1248.0