Methods for testing trends in mental health – is it really possible to compare ‘like with like’?

1. Methods for testing trends in mental health – is it really possible to compare ‘like with like’? Dr Stephan Collishaw Cardiff University collishaws@cardiff.ac.uk NCRM Research Methods Festival, Oxford, July 2014

2. Outline • Prevalence and burden • Trends in diagnosis – need for epidemiological data • Cross-cohort comparisons using symptom screens • Issues to think about in comparing ‘like with like’ • Results – adolescent mental health 1970s-2000s • Replication and validation • Trends in child mental health 1999-2008

3. Child psychiatric disorders: Burden and prognosis • 1 in 10 has a clinically significant psychiatric disorder • Impact on family life, friendships, learning • Suicide and self harm (3rd leading cause of death) • Long-term prognosis • Most child/adolescent disorders persist to adulthood • >50% of adult mental disorders have onset <18 years • Parenting, employment, social exclusion, illness, mortality • Economic burden Green et al., 2005; Kim-Cohen et al, 2003; Thapar et al., 2012; Windfuhr et al., 2008; Maughan et al., 2014

4. Diagnosis and treatment: autism, ADHD, depression, anxiety • Increased help seeking, diagnosis and treatment • Substantial increases in psychotropic medication • Rates increased 3-5 fold per decade 1990s and 2000s • Similar trends in many countries Getahun et al., 2013; Kosidou et al, 2010; Olfson et al., 2014; Stephenson et al, 2013

5. Trends in diagnosis and treatment Important for planning service provision But: Increases in referrals and diagnoses may be due to Increased public awareness & clinical recognition Changing diagnostic criteria and practice Treatment availability and perceived efficacy ‘Medicalisation’ of normal behaviour? Also: Majority still don’t access services Ford et al., 2007; Potter et al., 2012

6. Epidemiological evidence • Two major meta-analyses of depression and ADHD • Epidemiological studies using structured diagnostic interviews • Meta-analyses: no evidence of increase in depression or ADHD But • Variability in methods (samples, measures, diagnostic system) • Rates of depression range from <1%to >25% • ‘Noise’ and variability likely to make trends difficult to detect Costello et al., 2006; Polanczyk et al., 2014

7. ‘Like-for-like’ cross-cohort comparisons • Comparable representative cohorts with equivalent measures • e.g. UK cohorts since 1960s have included Rutter/SDQ • Threats to comparability • Selective attrition • Minor changes to questionnaire make a big difference • Disobedience: “applies somewhat” (33%) vs “sometimes” (75%) • Calibration can be effective for aligning non-identical instruments • Change in reporting Goodman et al., 2007

8. UK cross-cohort comparisons: 1974-1999 • Large nationally representative surveys (NCDS, BCS70, BCAMHS) assessed in 1974, 1986, 1999 • Age 15-16 • Parent rated Rutter or SDQ • Emotional problems • Conduct problems • Hyperactivity/inattention • Calibration data used to align SDQ and Rutter questionnaires • Study-specific weights using prior predictors of non-response Collishaw et al, 2004

9. Emotional problems: high scores Cohort 3 vs. cohort 2 OR = 1.72 N = 10,499 N = 7,293 N = 868 Collishaw et al, 2004

10. Conduct problems: high scores Total OR = 1.56 per cohort Collishaw et al, 2004

11. Hyperactivity: mean scores Collishaw et al, 2004

12. Limitations • Only parent reports • Imperfection of Rutter/SDQ calibration? • Crude measures • Are population shifts also occurring at extremes? • What about ‘change in reporting’? • Need for replication and validation

13. Replication: The Youth Trends study (1986 & 2006) Two nationally representative surveys of English youth 1986: BCS70 age 16 (N = 9,766) 2006: HSE follow-up ages 16-17 (N = 747) Identical self rated symptom screens (GHQ/Malaise) Questions Increase in youth-reported symptoms Variation in trends by severity? Collishaw et al, 2010

14. Adolescent emotional symptoms (youth reports) ES = 0.36; p < .001 ES = 0.13; p = .06 Collishaw et al., 2010

15. Trends by severity cohort differences significant at all thresholds, p<.01; Interaction p < .05 Collishaw et al, 2010

16. General shift in reporting?No change in hyperactivity Collishaw et al, 2010

17. Do trends reflect a change in reporting? • Shift in informant ‘thresholds’? (e.g. different expectations about normal behaviour) • Greater willingness to report problems than in the past? But • Specificity of findings (no increase in hyperactivity) • Validation using external criteria desirable…

18. Conduct problems:Age 30 outcomes NCDS & BCS70 cohorts Collishaw et al, 2004

19. Adolescent conduct problems and risk of pervasive adult dysfunction: 4+ adverse outcomes age 30 Collishaw et al, 2004

20. Child mental health trends: 1999-2008 • 1999: BCAMHS 7-year olds (n = 1034) • 2004: BCAMHS 7-year olds (n = 648) • 2008: MCS 7-year collection (n = 13,489) • Parent & teacher SDQ symptoms & impact • Weights used to adjust for attrition and stratified design Sellers et al, in press

21. Child mental health trends: 1999-2008 SDQ total and subscale mean scores all declined • Boys: total score effect size = -0.27 • Girls: total score effect size = -0.12 • Bigger drop in problem scores for boys than girls (p = 0.027) • Similar conclusions based on parent and teacher reports • Drop in children scoring in abnormal range (11%, 10%, 8%) • But: increase in impact of problems, e.g. classroom learning Sellers et al, in press

22. Conclusions • Comparing ‘like-with-like’ essential for testing trends • Replication and validation important • Long-term change in adolescent mental health • Recent data: improvements in child mental health • Latest data 2008, what has happened since?

23. Acknowledgements Barbara Maughan (KCL) Andrew Pickles (KCL) Robert Goodman (KCL) Anita Thapar (Cardiff) Ruth Sellers (Cardiff) Frances Gardner (Oxford) Jacqueline Scott (Cambridge) Ginny Russell (Exeter) National Centre for Social Research; Department of Health Medical Research Council; Nuffield Foundation; Waterloo Foundation

24. References Collishaw et al (2004). Time trends in adolescent mental health. J Child Psychol Psych, 45, 1350-1362. Collishaw et al (2010). Trends in adolescent emotional problems in England. J Child Psychol Psych, 51, 885-94. Costello et al (2006). Is there an epidemic of child and adolescent depression? J Child Psychol Psych, 47, 1263-71 Ford et al (2007). Child mental health is everybody’s business. Child Adolescent Mental Health, 12, 13-20. Getahun et al (2013). Recent trends in childhood ADHD. JAMA Pediatrics, 167, 282-8. Goodman et al (2007). Seemingly minor changes to a questionnaire. Soc Psych PsychEpi, 42, 322-327. Green et al (2005). Mental health of children and young people in GB, 2004. Palgrave Macmillan Kim-Cohen et al (2003). Prior juvenile diagnoses in adults with mental disorders. Archives General Psychiatry, 60. 709-17 Kosidouet al (2010). Recent trends. ActaPsychiatricaScandinavica, 22, 47-55. Maughan et al (2014). Adolescent conduct problems and premature mortality. Psych Med, 44, 1077-86. Olfsonet al (2014). National trends in the mental health care of children, adolescents and adults. JAMA Psych, 71, 81-90 Polanczyket al (2014). ADHD prevalence estimates across three decades. Int J Epidemiology, online first Potter et al (2012). Missed opportunities mental disorder in children of parents with depression. BJGP, 62, e487 Sellers et al (in press). Trends in parent- and teacher-rated emotional, conduct. J Child PsycholPsych, in press. Stephenson et al (2013). Trends in the utilisation of psychotropic medication. Austr New Zealand J Psychiatry, 47, 74-87. Thapar et al (2012). Depression in adolescence. Lancet, 379, 1056-67. Windfuhret al (2008). Suicide in juveniles and adolescents in the United Kingdom. J Child Psychol Psych, 49, 1155-65