Comparison of Kessler 10 from various data sources The Assessment of the Determinants and Epidemiology of Psychological Distress (ADEPD) Study

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1 Comparison of Kessler 10 from various data sources The Assessment of the Determinants and Epidemiology of Psychological Distress (ADEPD) Study The University of Adelaide Discipline of Psychiatry September 2009

2 2009 This work is copyright. It may be reproduced and the Discipline of Psychiatry at The University of Adelaide welcomes requests for permission to reproduce in the whole or in part for work, study or training purposes subject to the inclusion of an acknowledgment of the source and not commercial use or sale. Discipline of Psychiatry at The University of Adelaide will only accept responsibility for data analysis conducted by Discipline of Psychiatry at The University of Adelaide staff or under Discipline of Psychiatry at The University of Adelaide supervision. National Library of Australia Cataloguing-in-Publication entry Title: ISBN: Subjects: Comparison of Kessler 10 from various data sources [electronic resource] : the assessment of the determinants and epidemiology of psychological distress (ADEPD) study Report 2 / C.R. Koster... [et al.] (pdf) Distress (Psychology). Psychiatric epidemiology. Other Authors/Contributors: Koster, C. R. Dewey Number: National Library of Australia Cataloguing-in-Publication entry Title: ISBN: Subjects: Comparison of Kessler 10 from various data sources : the assessment of the determinants and epidemiology of psychological distress (ADEPD) study Report 2 / C.R. Koster... [et al.] (pbk) Distress (Psychology). Psychiatric epidemiology. Other Authors/Contributors: Koster, C. R. Dewey Number: Suggested citation: Koster, C., Taylor, A., Atkinson, M., Gill, T., Winefield, H., & Chittleborough C,. (September 2009). Comparison of Kessler 10 from various data sources. The Assessment of the Determinants and Epidemiology of Psychological Distress (ADEPD) Study. Discipline of Psychiatry, University of Adelaide

3 TABLE OF CONTENTS TABLE OF CONTENTS...2 LIST OF TABLES...4 LIST OF FIGURES...4 INTRODUCTION... 5 Background... 5 Psychological Distress... 6 METHODOLOGY... 7 Overall methodological considerations... 7 South Australian Monitoring and Surveillance System (SAMSS)... 7 Western Australia, Northern Territory, & South Australia (WANTS) Health... 8 National Health... 8 National of Mental Health and Wellbeing (NSMHW)... 9 North West Adelaide Health Study (NWAHS)... 9 Health Monitor (HM) Health Omnibus (HOS) Smoking, Nutrition, Physical Activity, Stress (SNAPS) RESULTS...13 Overall prevalence estimates for South Australia Overall prevalence estimates Other states Prevalence estimates by gender Prevalence estimates by age group CONCLUSION APPENDIX APPENDIX

4 APPENDIX

5 LIST OF TABLES Table 1: Definition of psychological distress based on Kessler 10 scores... 6 Table 2: Summary of methodology of studies Table 3: Prevalence of psychological distress within South Australia Table 4: Prevalence of psychological distress within selected states of Australia Table 5: Prevalence of psychological distress by gender within South Australia Table 6: Prevalence of psychological distress by gender within selected states of Australia.21 Table 7: Prevalence by psychological distress by age within South Australia Table 8: Prevalence by psychological distress by age within selected states of Australia LIST OF FIGURES Figure 1: Prevalence of psychological distress (K10) for surveys conducted in South Australia Figure 2: Breakdown of prevalence of psychological distress (K10) for each of the four categories for surveys conducted in South Australia Figure 3: Prevalence of psychological distress (K10) for each survey conducted in other states Figure 4: Breakdown of prevalence of psychological distress (K10) for each of the four categories for surveys conducted in other states Figure 5: Psychological distress by gender for surveys conducted in South Australia Figure 6: Psychological distress by gender for surveys conducted in other states Figure 7: Prevalence of psychological distress by age group for each survey conducted in South Australia Figure 8: Psychological distress by age groups for each survey conducted in South Australia

6 INTRODUCTION Background The Assessment of the Determinants and Epidemiology of Psychological Distress (ADEPD) study aims to provide a comprehensive analysis of the determinants of psychological distress (and psychological wellness) and mental health in the South Australian (SA) population 1. Previous reports published by the ADEPD team have shown that psychological distress is not experienced equally among all population groups (these reports are listed in Appendix 1). Additional details on ADEPD, including the full list of investigators, are included as Appendix 2. Previous ADEPD analyses have primarily focused on using the SA Monitoring and Surveillance System (SAMSS). The aim of this report is to compare prevalence estimates of psychological distress from a range of other relevant population data sources in addition to the SAMSS estimates. In undertaking this additional analysis, investigation of the age-group and gender differences have been produced. The data sources used in this report are: 1. South Australian Monitoring and Surveillance System (SAMSS) ( ); 2. Western Australia, Northern Territory and South Australia Collaborative Health (WANTS) (2000); 3. The SNAPS (Smoking, Nutrition, Alcohol, Physical activity and Stress) survey undertaken in Queensland, Northern Territory, Tasmania and Australian Capital (2004); 4. Australian Bureau of Statistics (ABS) National Health (NHS) (2007/08); 5. ABS National of Mental Health and Wellbeing (SMHWB) (2007); 6. North West Adelaide Health Study (NWAHS) (2007); 7. SA Health Monitor (HM) (2009); and 8. SA Health Omnibus (HOS) (2008). All analyses were limited to those aged 18 years and over. 5

7 Psychological Distress All population data sources analysed in this report included a measurement for psychological distress, the Kessler Psychological Distress Scale (K10), which is acknowledged as a simple, brief, valid and reliable instrument 2. The K10 is a ten-item questionnaire on non-specific psychological distress. The items are based on the level of anxiety and depressive symptoms experienced in the most recent fourweek period. Subjects report the frequency of each experience on a five point scale ranging from all of the time to none of the time. The scoring system used is based on the method developed by the Clinical Research Unit for Anxiety and Depression (CRUFAD) 3. In this method, five points are given to any answer of all of the time down to one point in a linear formulation for none of the time. This results in individual K10 scores being restricted to the range of 10 to 50 inclusive. Cut-off scores for low, moderate, high and very high psychological distress are based on the Collaborative Health and Wellbeing, where respondents with a score of were classified as having psychological distress (Table 1). Table 1: Definition of psychological distress based on Kessler 10 scores K10 score Level of psychological distress Low Moderate High Very high No psychological distress Psychological distress 6

8 METHODOLOGY Overall methodological considerations Details on the methodology of each of the data sources are listed below. Initially a range of other data sources were considered for possible inclusion in this analysis. Some were excluded from the analysis and a list of these, together with the reason for the exclusion, is included in Appendix 3. Comparison of estimates within SA was undertaken using the following data sets: South Australian Monitoring & Surveillance system (SAMSS), SA Health Omnibus (HOS), National Health (NHS), National of Mental Health and Wellbeing (NSMHW), North West Adelaide Health Study (NWAHS), Health Monitor (HM), and Western Australia, Northern Territory & South Australia Collaborative Health (WANTS) surveys. Comparison of estimates with other states/territories was undertaken with the data from the Smoking, Nutrition, Physical activity and Stress (SNAPS), WANTS, NHS, and NSMHW surveys. These surveys were included because they predominantly surveyed the whole state/territory rather than sub-sections of the community. The NHS and NSMHW data were ordered as customised data tables from the Australian Bureau of Statistics (ABS) while the other datasets were available for comprehensive analysis. All data sources were analysed overall, by gender and for the following age categories: 18-24, 25-34, 35-49, 50-64, 65 and over. A brief outline of the methodology of each of the studies is described below and summarised in Table 2. South Australian Monitoring and Surveillance System (SAMSS) SAMSS is a continuous, monthly, monitoring system commenced in July 2002 and conducted by the Population Research and Outcome Studies (PROS) Unit, SA Health 5. Approximately 600 South Australians of all ages are interviewed by Computer Assisted Telephone Interviewing (CATI) every month in order to monitor population trends in the prevalence of chronic conditions, associated risk factors and other determinants of health. All households in SA with a number listed in the Electronic White Pages (EWP) are eligible for selection in the SAMSS sample. A letter introducing the survey is sent to the household of each selected telephone number. Within each household, the person who had their birthday 7

9 last is selected for interview. Data are collected every month by a contracted agency and interviews are conducted in English. Between July 2002 and December 2008 n=34677 adults (18 years and over) were interviewed. The response rate for SAMSS is approximately 60% to 70% each month. Data are weighted by age, sex, area of residence to the population of SA aged 18 and over and the probability of selection in the household. Western Australia, Northern Territory, & South Australia (WANTS) Health A survey was undertaken in 2000 to compare chronic disease and risk factor estimates in SA, Northern Territory (NT) and Western Australia (WA) 4,6. All households in these states and territory with a telephone connected and the telephone number listed in the current version of the EWP were eligible for selection in the sample. Random samples were drawn separately for each state/territory and separate samples were drawn for each of the three geographic regions (metro/rural/remote) of the states/territory. The CATI system was used to conduct the interviews with at least six call-backs made to the telephone number to interview the randomly selected household member. The person chosen for interview was the person last to have a birthday. Different times of the day or evening were scheduled for each call-back. A total of n=7619 interviews were conducted (approximately n=2500 in each state/territory). Overall the response rate was 63.1%. In SA, n=2545 interviews were conducted with a response rate of 63.8%. Data were weighted by age, gender and probability of selection in the household to the ARIA regions (metropolitan, rural and remote). National Health The National Health (NHS) was conducted by the ABS from August 2007 to June Approximately 15,800 people from all States and Territories were included. One adult (aged 18 years and over) for each sampled dwelling were included in the survey. Both urban and rural areas in all States and Territories were included, but very remote areas of Australia were excluded. Non-private dwellings such as hotels, motels, hospitals, nursing homes and short-stay caravan parks were not included in the survey. Dwellings were selected at random using a multistage area sample of private dwellings. The initial sample selected for the survey consisted of approximately 20,000 dwellings. This was 8

10 reduced to a sample of approximately 15,800 after sample loss (e.g. households selected in the survey which had no residents in scope of the survey, vacant or derelict buildings, buildings under construction). Of the remaining dwellings 91% fully or adequately responded. To take account of possible seasonal effects on health characteristics, the sample was spread evenly and randomly across an eleven month enumeration period. Trained ABS interviewers conducted personal interviews with the selected residents. The data were weighted by the probability of selection within the household, age and sex. In SA n=1201 interviews were conducted 7. National of Mental Health and Wellbeing (NSMHW) In the 2007 National of Mental Health and Wellbeing (NSMHW), one randomly selected person (aged years) in each selected household was personally interviewed 8,9. Interviews were conducted between August and December 2007 using a Computer-Assisted Interview (CAI) questionnaire. CAI involves the use of a notebook computer to record, store, manipulate and transmit the data collected during interviews. Selected households were initially sent a Primary Approach Letter (PAL) by mail to inform the household of their selection in the survey and to advise that an interviewer would call to arrange a suitable time to conduct an interview. Interviews, including the household assessment, took on average 90 minutes per fully-responding household. Proxy, interpreted or foreign language interviews were not conducted. Of the eligible dwellings selected, there were 8,841 fully-responding households, representing a 60% response rate at the national level (also 60% in SA). In SA, n=1212 interviews were conducted. People usually resident in non-private dwellings, such as hotels, motels, hostels, hospitals, nursing homes, and short-stay caravan parks were not in scope. Data were weighted by probability of being selected in the survey, age and sex. North West Adelaide Health Study (NWAHS) The North West Adelaide Health Study (NWAHS) is a representative biomedical cohort study of randomly selected adults aged 18 years and over from the northern and western regions of Adelaide 10,11. All households in the northern and western areas of Adelaide with a telephone connected and a telephone number listed in the Electronic White Pages (EWP) were eligible for selection in the study and were initially randomly selected in Telephone numbers 9

11 that belonged to businesses, institutions and residential care facilities were excluded from the sample. The study excluded those people from a non-english speaking background who could not communicate sufficiently well with the telephone interviewer and who could not answer questions at the initial recruitment stage. Initially n=4060 participants were recruited. Data were obtained from 81% of these participants in Stage 2 of the study when participants were asked to return to the clinic for a second round of biomedical tests. Stage 1 data were weighted by region (western and northern health regions), age group, sex and probability of selection in the household to the Australian Bureau of Statistics 1999 Estimated Resident Population and the 2001 Census data. Stage 2 data was re-weighted using the 2004 Estimated Resident Population, incorporating participation in the three components, whilst retaining the original weight in the calculation. The study utilises many facets of research including a biomedical examination, self completed questionnaires and telephone (CATI) surveys. The Kessler 10 was administered in a followup telephone survey in 2007 and achieved a sample size of n=2996 with a response rate of 79.7%. Health Monitor (HM) The Health Monitor is a service provided by the Population Research and Outcome Studies Unit in which an opportunity is provided for health and welfare organisations to gather quality population information by including questions in the state-wide CATI survey conducted approximately three times per year 12,13. The EWP are used for random, non-replacement sampling of households with the objective of obtaining approximately 2000 interviews. Only one interview is conducted per household. Where more than one person aged 18 and over resided in the household, the respondent was the person who was last to have their birthday. In March 2009 the ADEPD study included the K10 in the survey. In total n=1933 interviews were conducted with a participation rate of 63.4%. Health Omnibus (HOS) The Health Omnibus is a shared cost, omnibus, survey to facilitate research among the SA community 14,15. Personal interviews are conducted with randomly selected adults (15 years or older) in randomly selected households. The sample is a multi-stage, systematic, clustered, area 10

12 sample based on collector districts throughout South Australia with a non-replacement sample. Only one interview is conducted per household. Where more than one person aged 15 or older resided in the household, the respondent is the person who was last to have their birthday. Up to six separate visits to selected households are made. In 2008, from n=4830 households selected, n=3034 face to face interviews were conducted, with a response rate of 62.8%. Smoking, Nutrition, Physical Activity, Stress (SNAPS) In 2004, SA and WA undertook a CATI survey on behalf of Queensland (QLD), Northern Territory (NT), Tasmania (TAS) and Australian Capital Territory (ACT) so that all Australian States and Territories would have comparable SNAPS data for All households in QLD, TAS, ACT and NT who had a telephone number listed in the July 2004 edition of the Electronic White Pages were eligible for selection in the sample. Within each household, the person, aged 18 or over, who had their birthday last, was selected for interview. There was no replacement for non-contactable persons. An approach letter, signed by an official from the Australian Government Department of Health and Ageing, was sent to every household for which there was sufficient address information provided by the Electronic Pages. The data were weighted for probability of selection and adjusted to reflect the age and sex distribution of the population in each of the jurisdictions surveyed. The overall response rate was 60.6%. 11

13 Table 2: Summary of methodology of studies Name of study State/s Organisation Study type Data collection method Selection type/weighting No. of interviews Response rate Time of survey SAMSS SA Population Research and Outcome Studies (PROS) Unit, SA Department of Health Representative computer-assisted telephone interview (CATI) surveillance system of 600 people in SA of all ages each month since July Sample randomly selected from electronic white pages (EWP). Telephone (CATI) Random sample selection from white pages - weighted 34, % each month July December 2008 (600 each month) WANTS SA, NT, WA CATI Data Pooling Pilot Project Conducted in 2000 in Western Australia, Northern Territory, South Australia (Collaborative Health and Wellbeing WANTS ) with identical questions to SAMSS. Telephone (CATI) Random sample from White Pages - weighted 2,545 in SA 64% 2000 SNAPS QLD, TAS, ACT, NT CATI Data Pooling Pilot Project Conducted in 2004 in Queensland, Tasmania, ACT, and Northern Territory (n=4832) with identical questions to SAMSS. Telephone (CATI) Random sample from White Pagesweighted 4,832 in total 61% 2004 NHS All states of Australia Australian Bureau of Statistics National cross-sectional survey conducted in 2007/08. Private dwellings randomly selected using multistage area sample. Face to face Random sample, multistage area sample 15,800 91% SMHWB All states of Australia Australian Bureau of Statistics National cross-sectional survey conducted in Private dwellings randomly selected using multistage area sample. Face to face Random selection - weighted % 2007 NWAHS NW suburbs of Adelaide PROS, TQEH, Uni of Adel, Uni of SA Biomedical cohort K10 data collected via telephone survey. Telephone (CATI) Random sample - weighted % 2007 HM SA PROS Representative computer-assisted telephone interview (CATI). Sample randomly selected from EWP. Telephone (CATI) Random sample from White Pages - weighted % 2009 HOS SA PROS / Uni Adel. Face to face interviews in autumn 2008, randomly selected from collector s districts as used by the ABS. Face to face Random selection by CD - weighted

14 RESULTS Overall prevalence estimates for South Australia The prevalence of psychological distress according to the K10 obtained from each of the data set relevant to SA is presented in Table 3. The prevalence ranged from 8.4% (95% CI ) to 12.9% (95% CI ). In addition, a breakdown of each level of psychological distress (low, moderate, high, very high) by the different surveys is presented (Table 3). Graphical presentation is presented in Figure 1 and Figure 2. The two highest prevalence estimates, NHS (12.9%) and NWAHS (12.6%), had the highest response rate of 91% and 80% respectively, while the lowest prevalence estimate, NSMHWB (8.4%), had the lowest response rate of 60%. The highest overall prevalence estimate was obtained in the 2007 NHS (12.9%) and this also had the smallest number of interviews (n=1201) undertaken. In contrast, the lowest prevalence estimate obtained (8.4%) was in the 2007 NSMHW with again a relatively small number of interviews completed (n=1212). The difference between these estimates was statistically significant. In terms of those with very high psychological distress, estimates ranged from 2.2% (95% CI ) in WANTS to 3.6% (95% CI ) in NHS. On the whole, interviews undertaken face to face (HOS, NSMHW and NHS) had higher prevalence estimates (2.6%, 3.5%, 3.6% respectively) than those undertaken by telephone (SAMSS, NWAHS, HM, WANTS 2.4%, 2.8%, 2.9%, 2.2% respectively). 13

15 Table 3: Prevalence of psychological distress measured using the K10 within South Australia South Australian National Study of Health Omnibus North West Adelaide Health Monitor National Health WANTS Monitoring and Surveillance System (SAMSS) Mental Health and Wellbeing (SA) Health Study (SA) (SA) 2000 Psychological Distress Psychological Distress (Score of 22 or more) Low n 3317/ / / / / / /2545 % ( ) ( ) ( ) ( ) ( ) ( ) ( ) Psychological Distress 4 categories n 24226/ / / / / / /2545 Score 10 to 15 % ( ) ( ) ( ) ( ) ( ) ( ) ( ) Moderate n 7085/ / / / / / /2545 Score 16 to 21 % ( ) ( ) ( ) ( ) ( ) ( ) ( ) High n 2490/ / / / / / /2545 Score 22 to 29 % ( ) ( ) ( ) ( ) ( ) ( ) ( ) Very high n 827/ / / / / / /2545 Score 30 to 50 % ( ) ( ) ( ) ( ) ( ) ( ) ( ) Note: NSMHWB includes 16 and 17 year olds. 14

16 Percentage SAMSS SMHWB HOS NWAHS HM NHS WANTS Figure 1: Prevalence of psychological distress (K10) for surveys conducted in South Australia 100% 90% 80% Percentage 70% 60% 50% 40% 30% 20% 10% very high high moderate low 0% SAMSS NSMHW HOS NWAHS HM NHS WANTS Figure 2: Breakdown of prevalence of psychological distress (K10) for each of the four categories for surveys conducted in South Australia 15

17 Overall prevalence estimates other states Table 4 reports the overall prevalence estimates, along with the breakdown into four categories of psychological distress, for the four surveys where comparisons were available for states/territories other than South Australia. Graphical presentation is found in Figure 3 and Figure 4. Similar to the SA results, the lowest and highest estimates were obtained from the two ABS surveys: 9.5% (95% CI ) from NSMHW and 12.0% (95% CI ) from NHS. The NHS estimates were significantly higher than the other three comparison surveys, in overall estimates and in terms of the prevalence of very high psychological distress. Further analysis can also be undertaken using the estimates from various data sources. A meta-analysis of all available prevalence figures would provide an overall prevalence estimate. This analysis is beyond the scope of this report but is recommended as a basis for on-going comparison of prevalence figures. 16

18 Table 4: Prevalence of psychological distress measured using the K10 within selected states of Australia SNAPS 2004 WANTS 2000 (Qld, TAS, ACT and NT) (SA, WA and NT) Psychological Distress National Health Study (SA, QLD, TAS, ACT, NT, WA, NT, VIC) National Study of Mental Health and Wellbeing (SA, QLD, TAS, ACT, NT, WA, NT, VIC)) Psychological Distress (K10) Score of 22 or more Low N 467/ / / /16015 % ( ) ( ) ( ) ( ) Psychological Distress 4 categories N 3334/ / / /16015 Score 10 to 15 % ( ) ( ) ( ) ( ) Moderate N 1018/ / / /16015 Score 16 to 21 % ( ) ( ) ( ) ( ) High* N 353/ / / /16015 Score 22 to 29 % ( ) ( ) ( ) ( ) Very N 114/ / / /16015 Score 30 to 50 % ( ) ( ) ( ) ( ) Note: NSMHWB includes 16 and 17 year olds 17

19 Percentage WANTS SNAPS NSMHW NHS Figure 3: Prevalence of psychological distress (K10) for each survey conducted in other states 100% 90% 80% Percentage 70% 60% 50% 40% 30% 20% 10% very high high moderate low 0% WANTS SNAPS NSMHW NHS Figure 4: Breakdown of prevalence of psychological distress (K10) for each of the four categories for surveys conducted in other states 18

20 Prevalence estimates by gender Prevalence estimates by gender are presented for SA specific and for non-sa specific surveys in Table 5 and Table 6, respectively. Graphs are presented in Figure 5 and Figure 6. A similar pattern to the overall estimates was apparent for males with high prevalence estimates being obtained in the NHS (12.3%) and low estimates from the NSMHW (5.8%). Females showed a different pattern with the highest estimate being found in the NWAHS (15.7%) and the lowest in WANTS (10.6%). Interestingly in the WANTS surveys there was very little difference between males and females (10.4% and 10.6%). Most other surveys resulted in marked differences between males and females with females always having higher prevalence estimates. These patterns were also apparent in the comparisons undertaken with data from the other states (Figure 6 and Table 6). Percentage SAMSS NSMHW HOS NWAHS HM NHS WANTS Male Female Figure 5: Psychological distress by gender for surveys conducted in South Australia 19

21 Percentage WANTS SNAPS NSMHW NHS Male Female Figure 6: Psychological distress by gender for surveys conducted in other states 20

22 Table 5: Prevalence of psychological distress as measure using K10 by gender within South Australia South Australian Monitoring and Surveillance System (SAMSS) National Study of Mental Health and Wellbeing (SA) 18+ Health Omnibus 18+ North West Adelaide Health Study Health Monitor Psychological Distress by Gender National Health Study (SA) WANTS 2000 (SA) Male n 1299/ / / / /935 73/ /1244 % ( ) ( ) ( ) ( ) ( ) ( ) ( ) Female n 2018/ / / / /989 82/ /1301 % ( ) ( ) ( ) ( ) ( ) ( ) ( ) Note: SMHWB includes 16 and 17 year olds Table 6: Prevalence of psychological distress by gender within selected states of Australia SNAPS 2004 WANTS 2000 National Health Study (Qld, TAS, ACT and NT) (SA, WA and NT) (SA, QLD, TAS, ACT, NT, WA, NT, VIC) Psychological Distress by Gender National Study of Mental Health and Wellbeing (SA, QLD, TAS, ACT, NT, WA, NT, VIC)) Male N 206/ / / /7950 % ( ) ( ) ( ) ( ) Female N 260/ / / /8066 % ( ) ( ) ( ) ( ) Note: NSMHWB includes 16 and 17 year old 21

23 Prevalence estimates by age group Prevalence estimates by age groups are presented for SA specific and for non-sa specific surveys in Table 7 and Table 8, respectively. Graphs are presented in Figure 7 and Figure 8. Inconsistent results were found for K10 prevalence estimates by age groups. Each age group (other than the 65 years and over group) recorded the highest prevalence of psychological distress at different times, with highest estimates found in the youngest age group in SAMSS (10.7%) and HM (12.1%); highest for the 25 to 34 year age group in the NWAHS (14.8%) and NHS (15.9%); highest for the 35 to 49 year age group in the HOS (11.2%); and highest for the 50 to 64 year age group in the NSMHW (13.5%) and WANTS (11.6%). In most instances the oldest age group (65 years and over) recorded the lowest estimates. Exceptions were observed in the NWAHS where 18 to 24 year olds had the lowest prevalence (10.0%) and the WANTS survey where 25 to 34 year olds had the lowest prevalence (9.2%). Similar patterns were apparent in the other state comparisons with a variety of age groups having the highest estimates but the oldest age group nearly always having the lowest estimates. Percentage SAMSS NSMHW HOS NWAHS HM NHS WANTS Figure 7: Prevalence of psychological distress by age group for each survey conducted in South Australia 22

24 a) 18 to 24 year olds b) 25 to 34 year olds Percentage Percentage SAMSS NSMHW HOS NWAHS HM NHS WANTS 0 SAMSS NSMHW HOS NWAHS HM NHS WANTS c) 35 to 49 year olds d) 50 to 64 year olds Percentage SAMSS NSMHW HOS NWAHS HM NHS 10.4 WANTS Percentage SAMSS NSMHW HOS NWAHS HM NHS WANTS e) 65 years and over Percentage SAMSS NSMHW HOS NWAHS HM NHS WANTS Figure 8: Psychological distress by age groups for each survey conducted in South Australia 23

25 Table 7: Prevalence by psychological distress by age within South Australia South Australian Monitoring and Surveillance System (SAMSS) National Study of Mental Health and Wellbeing (SA) Health Omnibus 18+ North West Adelaide Health Study Psychological Distress by Age Health Monitor National Health Study (SA) WANTS 2000 (SA) years n 420/3920 * 29/319 11/110 28/231 21/146 30/312 % 10.7 * ( ) ( ) ( ) (8.5-17) ( ) ( ) years n 630/ /366* 40/ /725 35/306 32/199 44/478 % * ( ) ( )* ( ) ( ) ( ) ( ) ( ) years n 987/ /366 90/ /905 53/504 46/337 80/768 % ( ) ( ) ( ) ( ) ( ) ( ) ( ) years n 801/ /278 72/700 77/678 60/502 37/295 59/508 % ( ) ( ) ( ) ( ) ( ) ( ) ( ) 65+ years n 479/6729 9/202 38/570 67/565 37/382 19/223 55/480 % ( ) ( ) ( ) ( ) ( ) (5.6-13) ( ) Note: NSMHWB includes 16 and 17 year old; * Youngest age group for NSMHW was from 16 to 34 combined. 24

26 Table 8: Prevalence by psychological distress by age within selected states of Australia SNAPS 2004 (Qld, TAS, ACT and NT) WANTS 2000 National Health Study (SA, WA and NT) (SA, QLD, TAS, ACT, NT, WA, NT, VIC) Psychological Distress by Age National Study of Mental Health and Wellbeing (SA, QLD, TAS, ACT, NT, WA, NT, VIC)) years n 88/ / / /2545 % ( ) ( ) ( ) ( ) years n 90/ / / /2812 % ( ) ( ) ( ) ( ) years n 143/ / / /4481 % ( ) ( ) ( ) ( ) years n 98/ / / /3772 % ( ) ( ) ( ) ( ) 65+ years n 49/ / / /2406 % ( ) ( ) ( ) ( ) Note: NSMHWB includes 16 and 17 year old 25

27 CONCLUSION A variety of prevalence estimates have been reported across the various data sets used in these analyses. In most instances, these estimates follow similar patterns (e.g. females higher than males, older people less likely to report psychological distress). Overall, approximately 3% of the adult population had very high psychological distress and approximately 70% of the adult population have very low levels of psychological distress. There are a variety of reasons why these estimates could vary. These include: sample size (with smaller samples having less power and wider confidence intervals), time frame of the survey (with possible seasonal differences to stress levels), and survey design (with face to face surveys generally having higher levels of psychological distress than telephone surveys). When comparing data from various sources, these issues as well as sampling selection, response rate, and approach technique are important issues to consider. It should also be noted that the higher the survey response rate, the higher the prevalence estimate of psychological distress. An explanation for this observation could be that those not experiencing psychological distress or health problems may be less likely to participate in health surveys. The selected data sets used in this analysis all show differences in regard to all of these issues. Thus any differences in the prevalence estimates obtained need to take these factors into consideration. Interestingly, for most comparisons, the highest and lowest estimates were from the two ABS surveys with the lowest being in the NSMHW and the highest in the NHS. This can perhaps be explained by the positioning of the K10 within the questionnaire, the lower than expected response rate in the NSMHW and the marketing of the survey as a mental health survey. If the two NHS and the NWAHS surveys are excluded most other estimates are within a comparable range. In summary, the prevalence of psychological distress does vary according to a wide range of factors. Comparisons of the prevalence of psychological distress across states or surveys need to consider differences in survey methods. In order to fully address psychological distress within the community, many demographics and related issues need to be considered when designing programs and developing policies. 26

28 APPENDIX 1 List of ADEPD Reports Major Reports 1 Determinants of Psychological Distress in South Australia - Report 1 2 A Literature Review, Determinants of Psychological Distress Report 2, Minor (4 page) Reports 3 Psychological Distress in South Australia: Prevalence of Trends and Projections 4 Housing and Psychological Distress in South Australia: Summary of Results 5 Chronic Conditions and Psychological Distress in South Australia: Summary of Results. 6 Current Mental Health and Psychological Distress in South Australia: Summary of Results 7 Employment Status and Psychological Distress in South Australia: Summary of Results. 8 Health Service Utilisation and Psychological Distress in South Australia: Summary of Results. Suggested Citation Freeman, M., Chittleborough, C., Winefield, H, Gill, T., & Taylor, A. (June 2008). Adelaide, SA: Discipline of Psychiatry, University of Adelaide/ Price, K., Gill, T., Winefield, H., Koster, C., Chittleborough, C., & Taylor A. (December 2008). Adelaide, SA: Discipline of Psychiatry, University of Adelaide/ Suggested Citation Shi, Z., Taylor, A., Gill, T., Koster C., Chittleborough, C., & Winefield H. (August 2009). Adelaide, SA: Discipline of Psychiatry, University of Adelaide Freeman, M., Chittleborough, C., Taylor, A., Winefield, H & Gill, T. (June 2008). Adelaide, SA: Discipline of Psychiatry, University of Adelaide. Koster, C., Freeman, M., Chittleborough. C., Gill, T., Taylor, A., & Winefield, H. (October 2008). Adelaide, SA: Discipline of Psychiatry, University of Adelaide Gill, T., Winefield, H., Koster, C., Taylor, A., & Chittleborough, C. (August 2009). Adelaide, SA: Discipline of Psychiatry, University of Adelaide Gill, T., Koster, C., Taylor, A., & Chittleborough, C. (August 2009). Adelaide, SA: Discipline of Psychiatry, University of Adelaide. Adelaide, SA: Discipline of Psychiatry, University of Adelaide Koster, C., Gill, T., Chittleborough, C., Taylor, A., & Winefield, H. (August 2009). Adelaide, SA: Discipline of Psychiatry, University of Adelaide 9 Mapping Psychological Distress in SA. Gill T, Taylor A, Winefield H, Koster C, Chittleborough C, Hugo G. (September 2009). Discipline of Psychiatry, University of Adelaide. 27

29 Other Reports 10 Consensus Statement on Chronic Disease and Psychological Distress 11 Psychological Distress and Psychological Well- Being - Kessler 10 and Various Well-Being Scales Suggested Citation A Taylor, A., Chittleborough, C., Gill, T., Winefield, H., Koster, C., & Hornibrook, L. (January 2009). Adelaide, SA: Discipline of Psychiatry, University of Adelaide. Winefield, H., Taylor, A., Gill, T., Pilkington, R., & Koster, C. (September 2009). Adelaide, SA: Discipline of Psychiatry, University of Adelaide. 12 Comparison of K10 from various data sources. Koster, C., Taylor, A., Atkinson, M., Gill, T., Winefield, H., & Chittleborough, C. (September 2009). Adelaide, SA: Discipline of Psychiatry, University of Adelaide 13 K10: Assessing Mental Health Distress in South Australia 14 Determinants of Psychological Distress - Final Report Hawthorne, G. (2009). Department of Psychiatry, The University of Melbourne For The Assessment of the Determinants and Epidemiology of Psychological Distress (ADEPD) Study, The University of Adelaide. Gill, T.K., Taylor, A.W., Winefield H., Chittleborough C.R., & Koster C.R. (September 2009). Adelaide, SA: Discipline of Psychiatry, University of Adelaide. 28

30 APPENDIX 2 List of Investigators The Assessment of the Determinants and Epidemiology of Psychological Distress (ADEPD) study was funded by the Strategic Health Research Program, South Australian Department of Health. The ADEPD team would like to acknowledge the contributions of the investigators involved with the project: Professor Helen Winefield, Discipline of Psychiatry, University of Adelaide; Dr Catherine Chittleborough, Population Research and Outcome Studies Unit, SA Health; Dr Anne Taylor, Population Research and Outcome Studies Unit, SA Health; Dr Tiffany Gill, Population Research and Outcome Studies Unit, SA Health; Professor Fran Baum, Department of Public Health, Flinders University of South Australia; Professor Robert Goldney, Discipline of Psychiatry, University of Adelaide; Professor Janet Hiller, Discipline of Public Health, University of Adelaide; Professor Graeme Hugo, Geographical and Environmental Studies, University of Adelaide; Professor Robyn McDermott, Division of Health Sciences, University of South Australia; Professor John Spoehr, Australian Institute for Social Research, University of Adelaide Mr Graeme Tucker, Health Statistics Unit, SA Health. ADEPD staff employed during the project were: Carmen Koster, Population Research and Outcome Studies Unit, SA Health; Leanne Hornibrook, Population Research and Outcome Studies Unit, SA Health Matthew Freeman, Population Research and Outcome Studies Unit, SA Health Jacqueline Balacano, Population Research and Outcome Studies Unit, SA Health 29

31 APPENDIX 3 List of surveys assessed Proposed surveys from the grant application are listed below as well as the inclusion status of each survey. Analyses compared psychological distress, as measured by the Kessler 10 instrument, so only surveys including this instrument were used for comparison. Some surveys were excluded due to a different geographical spread than state level or an insufficient sample size. SURVEY NAME AGENCY K10 MEASURE INCLUSION IN COMPARISON 1. South Australian Monitoring and Surveillance System (SAMSS) Population Research and Outcome Studies (PROS) Unit, SA Department of Health Yes Yes 2. North West Adelaide Health Study SA Department of Health, University of Adelaide, University of South Australia, The Queen Elizabeth Hospital, The Lyell McEwin Hospital Yes Yes 3. Health Omnibus PROS Unit, SA Department of Health Yes Yes 4. Greater Green Triangle Risk Factor Study 16 Flinders University, Deakin University Yes (2 surveys) No, not state level and sample size too small 5. SNAPS CATI Data Pooling Pilot Project 6. National Health Australian Bureau of Statistics 7. National of Mental Health and Wellbeing (SMHWB) 8. Australian Longitudinal Study on Women s Health (ALSWH) Household, Income and Labour Dynamics in Australia (HILDA) survey 18 Australian Bureau of Statistics The University of Newcastle, The University of Queensland, Research Centre for Gender and Health Yes Yes Yes No Yes Yes Yes No, K10 not used The University of Melbourne No No, K10 not used 30

32 REFERENCES 1 Assessment of the Determinants and Epidemiology of Psychological Distress (ADEPD) Study. Available at: 2 Kessler RC, Barker PR, Colpe LJ, Epstein JF, Gfroerer JC, Hiripi E et al. Screening for serious mental illness in the general population. Archives of General Psychiatry 2003; 60(2): Andrews G, Slade T. Interpreting scores on the Kessler Psychological Distress Scale (K10). Australian and New Zealand Journal of Public Health 2001; 25(6): WANTS Health West, 2000 Collaborative Health and Wellbeing Design and Methodology. Western Australian Government. Perth: Western Australia, Population Research & Outcome Studies. SA Monitoring and Surveillance System (SAMSS). Available at: 6 Taylor A, Daly A, d'espaignet E, Wilson D, Eshpeter J, Measey M. Collaborative Health and Wellbeing CATI of Adults living in Western Australia, Northern Territory and South Australia: Report 1: Summary of Results by State/Territory - September Australian Bureau of Statistics. National Health : Users Guide Electronic Publication. ABS Cat. No ABS, Canberra, Available at: o=4364.0&issue= Australian Bureau of Statistics. National of Mental Health and Wellbeing of Adults, Users Guide. ABS Cat. No ABS, Canberra, Australian Bureau of Statistics. National of Mental Health and Wellbeing of Adults. Available at: sign?opendocument 10 Grant JF, Chittleborough CR, Taylor AW, Dal Grande E, Wilson DH, Phillips PJ, Adams RJ, Cheek J, Price K, Gill T, Ruffin RE, and the North West Adelaide Health Study Team. The North West Adelaide Health Study: detailed methods and baseline segmentation of a cohort for selected chronic diseases. Epidemiologic Perspectives & Innovations 2006; 3:4. 11 North West Adelaide Health Study. Available at: 12 Population Research and Outcome Studies. The Health Monitor (HM) Methodology. Brief Report South Australian Department of Health, Adelaide Population Research & Outcome Studies. Health Monitor. Available at: 14 Population Research and Outcome Studies. The Health Omnibus (HOS) Methodology. Brief Report South Australian Department of Health, Adelaide Population Research & Outcome Studies. Health Omnibus. Available at: 31

33 16 Heistaro S, Janus E, Dunbar J, Laatikainen T, Kilkkinen A (eds). Greater Green Triangle Risk Factor Study: Basic Report. Greater Green Triangle University Department of Rural Health Lee C. Women's Health Australia: What do we know? What do we need to know? Progress on the Australian Longitudinal Study of Women's Health Brisbane: Australian Academic Press, Watson N, Wooden M. The Household, Income and Labour Dynamics in Australia (HILDA) : Wave 1 Methodology. Technical Paper Series No. 1/02. Melbourne Institute of Applied Economic and Social Research