4327.0 - National Survey of Mental Health and Wellbeing: Users' Guide, 2007
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 11/02/2009
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6. OTHER SCALES AND MEASURES
KESSLER PSYCHOLOGICAL DISTRESS SCALE (K10) The Kessler Psychological Distress Scale (K10) is a widely used indicator, which gives a simple measure of psychological distress. It is not a diagnostic tool, but is an indicator of psychological distress. Research has found a strong association between high scores on the K10 and the diagnosis of Anxiety and Affective disorders through the current WMH-CIDI (version 3.0). There is also a lesser, but still significant association between the K10 and other mental disorder categories, or the presence of any current mental disorder (Andrews & Slade, 2001). The K10 is based on a person's emotional state during the 30 days prior to the survey interview. People were asked a series of 10 questions, about how often they felt:
02 - nervous; 03 - so nervous nothing could calm them down; 04 - hopeless; 05 - restless or fidgety; 06 - so restless that they could not sit still; 07 - depressed; 08 - so depressed that nothing could cheer them up; 09 - that everything was an effort; and 10 - worthless. For each question, an answer was provided using a five-level response scale, based on the amount of time a person reported experiencing the particular problem. The response scale corresponded to the following:
If a person endorsed 'none of the time' for questions 2, 5 or 7 they were not asked the follow-on questions at 3, 6 or 8, but were skipped to subsequent questions at 4, 7 or 9 respectively. Scores for the 10 questions were put together, with a minimum possible score of 10 and a maximum possible score of 50. Low scores indicate low levels of psychological distress and high scores indicate high levels of psychological distress. The scores output for this survey were:
Four additional questions were asked after the set of 10, which explored feelings of anger in the 30 days prior to interview. These questions were aimed at monitoring the level of anger throughout the Australian community. People provided a response based on the same rating scale as the K10. The first question asked how often in the preceding 30 days people were 'mad or angry'. All people who gave a response, other than 'none of the time', were subsequently asked how often in the preceding 30 days they:
These questions were not considered when scoring the responses to the K10 and forming the output categories. Comparison with the 1997 survey In 1997, questions 8 and 9 of the K10 were asked in the reverse order. Additionally, the endorsement of 'none of the time' for question 7 did not result in a person being skipped to question 9 in the 1997 survey. There were also slight changes to the question wording, with the 1997 survey referring to the four weeks prior to interview, compared to the 30 days prior to interview in 2007. The wording for question 8 also differed slightly in 1997, asking 'about how often the person felt so sad nothing could cheer them up'. The 1997 survey did not include any questions on feelings of anger. SEVERITY MEASURE The severity measure assesses the impact a mental disorder has on a person through an attributed level of impairment. Higher levels of severity may be associated with affective (mood) disorders, as well as with comorbid mental disorders (Kessler et al, 2005). In the CIDI, the severity of 12-month symptoms can be measured through the Sheehan Disability Scale administered in each diagnostic section, and through disorder-specific clinical severity scales. Comparisons of Sheehan Disability Scale scores across diagnoses allow for comparison of the severity distributions of different mental disorders. The disorder-specific scales explore the depth of distress caused by a disorder through fully-structured versions of the standard clinical severity scales. For example, the Young Mania Rating Scale is contained within the Mania Disorder Module and is used to assess the severity of 12-month symptoms. The rating is based on responses to an 11-item scale, which asks about the person's most severe episode lasting four days or longer and whether they experienced changes in:
The person was asked to select one of five statements that most accurately described their experience for each of the 11 items. These statements were given a rating on a scale of '1 to 5', where 1 = no change. Level of severity For people who were diagnosed with a lifetime mental disorder and had symptoms in the 12 months prior to interview the level of the severity of their impairment was calculated. The severity measure draws upon a number of criteria, based on the endorsement of particular questions in the survey interview. The calculations used for this survey are outlined in the following segments. The responses to these questions are used to provide an overall indication of the severity of impairment, by the following three levels: Several versions of the severity measure have been created for use with the survey data, including:
Both the WMH-CIDI version and the New Zealand version of severity are based on the DSM-IV. Adjustments were made to the severity measure for both of these versions to enable a severity calculation for the ICD-10. The Australian version was adapted from the New Zealand version and includes both DSM-IV and ICD-10 calculations. The criteria used to determine the level of severity for all versions are provided below, along with any additional criteria for each of the specific versions. Severe A person was considered to have a severe level of impairment if any one of the following occurred in the 12 months prior to interview:
More information on the calculation of functional impairment and the Global Assessment of Functioning (GAF) Score is provided later in this chapter. The following criteria were also considered:
Moderate A person was considered to have a moderate level of impairment if they had a 12-month mental disorder and they:
The following criteria were also considered:
Mild A person was considered to have a mild level of impairment if they had a 12-month mental disorder and they were not classified as severe or moderate. Global Assessment of Functioning (GAF) Score The National Comorbidity Survey Replication (NCS-R), was conducted in the United States of America in 2001-02. The survey had a sample of approximately 10,000 respondents aged 18 years and over. The survey made an overall assessment of functional impairment using several definitions of severity. Subsequent surveys have adopted an approach which uses a 'predicted' Global Assessment of Functioning (GAF) Score. For this survey the predicted GAF Score was calculated using:
Days out of role The maximum number of days out of role was derived from responses to various questions within the diagnostic modules (eg Depressive Episode, Agoraphobia, Mania, etc). The calculation did not include any days out of role for Substance Use disorders, except for the Australian version. The maximum number of days out of role was then categorised as follows:
People who had 'no interference' on the Sheehan Disability Scale were assigned '0' days. Where there was a 'not known' or 'not stated' value for the days out of role, a median number of days out of role was assigned. Sheehan Disability Scale The Sheehan Disability Scale was used to assess the level of interference in four life domains during the worst period of symptoms in the 12 months prior to interview. The four domains are:
The Sheehan Disability Scale ranges from '0 to 10', with each number being attributed a notional level of interference:
People were asked to select the number that best described the level of interference their symptoms had on each of the domains. From responses in each of the diagnostic modules, a score was calculated for each domain, representing mild, moderate or severe interference. The calculation did not include any days out of role for Substance Use disorders, except for the Australian version. The scores were as follows:
An overall level of impairment (mild, moderate or severe) was derived using each of the domain scores. Where a person had 3 or 4 domains rated as severe, they received an overall assessment of 'severe'; where they had 2 to 4 domains rated as mild, they received an overall assessment of 'mild'; otherwise they received an overall assessment of 'moderate'. Predicted GAF Score The predicted Global Assessment of Functioning (GAF) Score is based on the following: GAF Score of 50 or less
GAF Score of 51 or more
Comparison with the 1997 survey The 1997 survey did not collect specific information for a severity measure. However, it may be possible to calculate a proxy measurement using responses to some questions, such as whether something interfered with the person's life or activities a lot. In comparison, the 2007 survey included extensive questions designed to calculate severity of impairment. DELIGHTED-TERRIBLE SCALE The Delighted-Terrible Scale seeks an overall rating from the respondent regarding their life as a whole for the year preceding the survey interview and for their expectations of the future. There were seven response categories:
Each response corresponds to a scale of '1 to 7', where 1 = terrible and 7 = delighted. Comparison with the 1997 survey The same scale was used in 1997. However, the question was included at a different point in the survey. In 1997, the question appeared after the K10 and before questions on physical conditions. In 2007, the question was asked after the self-assessed health rating and before the screener. SELF-ASSESSED HEALTH RATING This self-assessed measure is based on the person's overall physical and mental health both generally and in comparison to the period one year prior to the survey interview. People were asked to rate both their physical and mental health on the following scale:
The person's general health at the time of the survey interview compared to one year prior was assessed as:
If the person reported that their health was better/worse than one year prior, they were then asked if this difference was:
Comparison with the 1997 survey A less detailed measure was used in 1997. Only one question was asked about the person's general health. The person then provided a self-assessed rating based on a scale from 'excellent to poor'. No subsequent questions were asked which compared the person's health one year prior to the survey interview. In 1997, this question was asked prior to the Short-Form 12 set of questions. In 2007, the questions were asked after the 'Days out of role' questions and prior to the 'Delighted-Terrible Scale'. MAIN PROBLEM Where a person reported one or more physical conditions and/or was likely to have one or more 12-month mental disorders, they were asked which of their problems troubled them the most. The list of physical conditions included:
The list of symptoms suggesting the likely diagnosis of a 12-month mental disorder included:
Comparison with the 1997 survey The 1997 survey also asked people which of their physical and/or mental health problems troubled them the most. However, the list of possible conditions or disorders differed to the 2007 survey. The 1997 survey included people whose symptoms suggested an organic mental disorder, a personality disorder or neurasthenia. Additionally, people were asked six questions about functioning in their daily activities prior to being asked about their main problem. A person had to endorse at least one of the six questions and have symptoms that suggested one or more physical conditions and/or mental disorders to be asked about their main problem. PSYCHOSIS SCREENER Psychoses are mental disorders in which the person has strange ideas (eg that they are being spied on by aliens) or experiences (eg hearing voices when there is no one there) which are unaffected by rational argument and are out of keeping with the views of any culture or group to which the person belongs. The survey included four questions designed to screen for the likely presence of psychosis. The questions were not designed to provide a diagnosis. There is no standard output from these items, but data may be available to suit individual requirements. People were asked about whether they ever felt:
They were also asked whether they had these types of feelings or experiences in the 12 months prior to interview and whether a doctor had ever told them that they may have schizophrenia. Visions seen or voices heard during dreams or half-asleep, or under the influence of alcohol or drugs are excluded. Comparison with the 1997 survey The 1997 survey also included a psychosis screener. In 1997, the emphasis of the questions was on ideas or experiences in the 12 months prior to interview, rather than in the person's lifetime. The question wording was the same, except for the differences in time-frame. For example, in 2007 people are asked, 'Have you ever had a feeling that people were too interested in you?' whereas in 1997 they were asked, 'In the past 12 months, have you had a feeling that people were too interested in you?' SUICIDAL BEHAVIOUR An attempt of suicide may be a sign that a mental illness exists or is developing. In this survey, people were asked about suicidal behaviour in their lifetime and in the 12 months prior to interview. More detailed questions were asked about suicidal behaviour in the 12 months prior to interview. Suicidal behaviour includes:
Ideation must have been experienced at some point in the person's lifetime in order to be asked about ideation in the 12 months prior to interview. People were also asked to provide their age:
People were only asked about suicidal plans and attempts if they had experienced ideation. If a person had ever made a plan for committing suicide they were asked:
If a person had ever attempted suicide they were asked how many times they had attempted suicide. If they had only one attempt they were asked whether this had occurred in the 12 months prior to interview. If the attempt was more than 12 months prior, the person was asked their age when they attempted suicide. If a person had more than one attempt, they were asked their age the first time they attempted suicide. They were then asked to select one of the following three statements that best described their situation when they first attempted suicide:
People were then asked their age the last time they attempted suicide and to select one of the above three statements in relation to their last attempted suicide. People who had attempted suicide during the 12 months prior to interview were asked whether their attempt:
They were also asked the method used, from the following list:
People could also describe some other type of method. If a person had used more than one type of method (eg overdose of prescription medication, then razor), the first method used for the attempt was recorded. Suicidal behaviour related to Depression The Depression module contained questions which asked whether a person had:
If endorsed, people were asked a series of questions about suicidal behaviour in their lifetime and in the 12 months prior to interview. A person must have said they thought about committing suicide in order to be asked if they had made a plan or attempt. The suicide questions in the Depression module refer to the period of several days/two weeks or longer during the episode when the person's symptoms (sadness, discouragement, loss of interest and other problems) were most severe and frequent. Comparison with the 1997 survey The 1997 survey contained three questions about suicide:
The first question must have been endorsed in order to be asked the second question, and the second question must have been endorsed in order to be asked the subsequent question. In 1997 there were also questions regarding 'Thoughts of death' in the Depression module. The questions covered thoughts, plans and attempts. The 2007 survey included separate questions on suicidal behaviour in the Depression module. For more information see 'Depressive Episode' in Chapter 3. MINI-MENTAL STATE EXAMINATION (MMSE) The MMSE is a brief assessment that can be used to screen for the presence of cognitive impairment. The assessment is widely used in hospitals throughout the world. However, it does not identify any particular organic mental disorders. In this survey, the MMSE was used to exclude people without sufficient cognitive ability (score of 18 or less) from the survey interview. Only people aged 65-85 years were assessed. People were asked to compare their memory to other people their age and give themselves a rating:
They were then asked to compare their memory at the time of interview to how it was five years earlier and rate it on the same scale. People were asked to respond to a number of questions and to perform tasks that tested: orientation, registration, calculation and attention, recall, language and visual construction (eg spelling the word 'world' backwards, naming objects and copying a drawing). For each question or task, the interviewer allocated a score for the person's response, based on the following:
The scoring for the MMSE is based on correct responses. A correct response is based on the following:
The MMSE has a maximum score of 30 points. A score of 23 or less is generally accepted as indicating the presence of cognitive impairment. The severity of cognitive impairment may be classified as:
Where people could not complete tasks due to physical impediments or because they were unable to read or write, their MMSE score was pro-rated. For people whose score was 18 or less the survey interview was terminated. There were only five instances where an interview did not proceed due to low MMSE scores. Comparison with the 1997 survey In 1997, the introductory question about problems with memory only relates to the 12 months prior to interview. There are differences in some of the subsequent questions, such as sequencing or word changes. For example, in 1997 people were asked to provide their address, whereas in 2007 they were asked the name of their street and street number. In 2007, the task related to spelling the word 'world' was asked in two parts, first people had to spell the word and then they had to spell it backwards (dlrow), whereas in 1997 people were only asked to spell the word 'world' backwards. In 1997, people did a paper folding exercise, wrote a complete sentence and then did a hand drawing. In 2007, the order of these activities differed, people wrote a complete sentence, did a hand drawing and then did the paper folding exercise. In 1997, the MMSE was included after the mental disorder modules and prior to the personality disorder screener. While in 2007, the MMSE was included prior to the screener for the mental disorder modules. The output categories for MMSE scores in 1997 were also different. A score of '18 to 23' indicated mild cognitive impairment and a score of '17 or less' indicated severe cognitive impairment. Document Selection These documents will be presented in a new window.
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