Classification & Epidemiology in Child Psychiatry

1. Classification & Epidemiology in Child Psychiatry John McLennan University of Calgary Jan 17, 2013

2. Outline • Why classify mental phenomena? • A little history of DSM • Categories and/or dimensions • Quebec epidemiology study • Great Smoky Mountain Study

3. Why classify mental phenomena? • May aid communication • May reduce/summarize complex problems • May inform triage and treatment decisions • May advance science • Reliability • Validity • Comparability • Precision

4. Any concerns about classifying? • Labelling….stigma • Foster/encourage excessive belief/confidence in (i.e., going beyond the science)… • The precision • Explanatory power • Independent existence (vs. social construction, societal bounded notions) • In existence of discrete entities • Mask substantial heterogeneity • E.g., in ADHD, autism

5. History of categorizing in the USA – pre-DSM • 1840 census: • 1 category: “idiocy/insanity” • Statistical purposes • 1880 census: • 7 categories: mania, melancholia, monomania (e.g., kleptomania), paresis, dementia, dipsomania (e.g., alcoholism), epilepsy • 1917 Statistical Manual for the use of Institutions for the Insane: • 22 categories

6. Diagnostic & Statistical Manual of Mental Disorders (DSM) • DSM-I (1952) • Glossary of descriptions of diagnostic categories • 106 categories • Included the notion of “reaction” (Adolf Meyer), i.e., reacting to biopsychosocial factors DSM: History of the Manual (APA ,2012)

7. Diagnostic & Statistical Manual of Mental Disorders (DSM) • DSM-II (1968) • Move away from reaction • Psychodynamic influence • 182 categories

8. DSM-II • Runaway reaction of childhood • “Individuals with this disorder characteristically escape from threatening situations by running away from home for a day or more without permission. Typically they are immature and timid, and feel rejected at home, inadequate, and friendless. They often steal furtively”. APA - DSM-II (1968) p.50

9. DSM-III • DSM-III – 1980 • 265 diagnoses • Explicit diagnostic criteria • Influenced by Research Diagnostic Criteria • Multi-axial system • Emphasis on description (vs. theory of etiology) • DSM-III R (Revised) – 1987 • 292 categories • To address inconsistency and lack of clarity

10. DSM-IV • Task Force • Systematic literature reviews • Reanalysis of data sets • Focused field trials • 16 major diagnostic classes • 297 categories • 1st section: “Disorders usually first diagnosed in infancy, childhood or adolescence” • DSM-IV (TR) - 2000

11. Disorders usually first diagnosed in infancy, childhood or adolescence • Mental Retardation (Axis II) [“Intellectual Disability”] • Learning Disorders • Motor Skills Disorders • Communication Disorders • Pervasive Developmental Disorders • Attention-deficit and disruptive behavior disorder • Feeding and eating disorders of infancy and childhood • Tic Disorders • Elimination Disorders • Other Disorders of Infancy, Childhood or Adolescence • In addition to application of most of the other DSM-IV diagnoses to children and adolescent e.g., mood and anxiety disorders

12. DSM-5 • Release expected May 2013 • www.dsm5.org • Section of proposed organizational structure • Neurodevelopmental Disorders • Intellectual Developmental Disorders • Communication Disorders • Autism Spectrum Disorder • Attention Deficit/Hyperactivity Disorder • Specific Learning Disorder • Motor Disorders • [Others….depression, anxiety housed in those categories]

13. DSM-5 – Child section proposed changes • Various content changes • E.g., in ADHD • Modifications • E.g., Pervasive Development Disorders • Drop Rett’s Disorder • Subsume Asperger’s Disorder into an Autistic Spectrum Disorder • Collapse social and communication impairments into a combined criterion • Create a “sub-syndromal “ disorder “Social Communication Disorder” to be housed under the Communication Disorder group • New Disorders • E.g., Temper Dysregulation Disorder with Dysphoria

14. DSM-5 – Child section proposed changes • Temper Dysregulation Disorder with Dysphoria • Temper outbursts (severe, frequent) • Negative mood between outbursts • At least 6 years of age • Not meeting mania criteria

15. Other classification systems • International Classification of Disease (ICD) • 10th edition (1992)….[11th edition partial available, “official?” release in 2015) • Coordinated efforts with DSM system • Chapter 5: Mental and behavioural disorders • Disorders of psychological development • Behavioural & emotional disorders with onset usually occurring in childhood & adolescence • Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood (0-3 years) • Axis I: Primary diagnosis • Axis II: Relationship Disorders (e.g., angry/hostile) • Axis V: Functional Emotional Developmental Level • DSM-PC (Primary Care) • Primary care physicians – clinical practice • Child & Adolescent Version • American Academy of Pediatrics

16. Categorical vs. dimensional • What are the issues?

17. Categories vs. Dimensions Coghill and Sonuga-Barke, 2012, p.469

18. Dimensional vs. Categorical • Dimensional –degrees • May be more reflective of underlying distribution • Provides index of severity • Categorical – yes/no; present/absent • May align with service and treatment decision making • Consistent with “preference” of human cognitive processes (clinician, patient, caregiver)….we are “natural categorizers” (Coghill & Sonuga-Barke, 2012) • Usefulness may depends on the situation • Not unique to (child) psychiatry • E.g., hypertension

19. IQ distribution and Mental Retardation Jensen 1969

20. Statistical approaches • Newer statistical model (coherent cut kinetics - Meehl) aimed to identify patterns of discontinuity in underlying structure of observed data (and hence can test between categorical and dimensional models) • Try to determine whether a particular disorder represents a discreet causal entity (a real category) or one end of a continuum (part of a dimension) Coghill and Sonuga-Barke, 2012

21. Evidence for taxons (Coghill & Sonuga-Barke, 2012) • Taxon • A discrete entity that is qualitative different from normal range • Insecure attachment classification • Continuous model a better fit • Anxiety sensitivity • Evidence for a taxon • Depression • Continuous model a better fit for adolescent depression (except maybe melancholy) • Evidence of taxon for child depression • PTSD/reaction • Dimensional model a better fit • ADHD • No evidence for a taxon

22. Combined use • Categorical diagnosis + quantitative measure of severity, for example • Diagnosis of depression + CDI score • Diagnosis of ADHD + MTA-SNAP-IV score • Other areas of medicine • COPD + measures of lung function

23. Classification issues • Future-?: • Course • Cause • Response to treatment • Genetic underpinning • Underlying “pathophysiology”

24. Epidemiology • Definition: • Study of the distribution, determinants and causes of disease in human populations

25. Key epidemiology questions • How many people (proportion of people) have a particular disease at any one time? • Prevalence: point, period of time, lifetime • How many new cases of this disease will occur during a defined period? • Incidence • Which group in the population is at highest risk for specific diseases? • Are there characteristics of certain environments that increase the risk of particular diseases? • What are the most effective methods of preventing or controlling the spread of specific diseases? Costello et al., 2004

26. A Key Measurement Issues: Different informants • Type: parents, child, teacher, others (e.g., clinician) • Agreement • Achenbach et al., 1987- correlations • 0.60 for similar informants • 0.28 different types of informants • 0.22 with child report • Reporting on different contexts: home, school, community • How to manage information from multiple informants? • Combine data (e.g., “and” vs. “or”)

27. Epidemiological study examples • Quebec Study • Great Smoky Mountain Study

28. Quebec Child Mental Health Survey • 1992 • Cross-sectional • Prevalence of DSM-III-R disorders • 6 months prevalence • N=2400 (representative); 6-14 years of age • Response rate: 83.5% • Informants: parent & child & teacher (6-11y olds) • Diagnostic Interview Schedule for Children (DISC) • Dominic Questionnaire (6-11 y olds)

29. Quebec Child Mental Health Survey • ADHD: 1.8-9.8% • Teacher>parents>children • Younger>older • Boys>girls

30. Quebec Child Mental Health Survey • Oppositional Defiant Disorder 0.7-5.8% • Child>parent>teacher (younger) • Parent>child (older) • Conduct Disorder 0.2-2.3% • Child>teacher>parent • Boys>girls • Younger>Older

31. Quebec Child Mental Health Survey • Separation Anxiety Disorder 0.7-4.9% • Child>parent (younger) • Simple phobia 1.3-14.6% • parent>child • Most common • Substantial drop with impairment criteria • Overanxious/GAD 1.7-5.5% • Child>parent (younger) • Parent>child (older)

32. Quebec Child Mental Health Survey • Depressive Disorder 1.0-3.5% • Child>parent • Girls>boys (older) • Older girls>younger girls • Younger boys>older boys • One or more disorders 9.6-32.4% • Child and/or parent (32.4%) • Parent + impairment: (9.6%)

33. Longitudinal studies • Rare in child psychiatry • Essential for prospectively determining incidence and duration patterns

34. Great Smoky Mountains Study • Cross-sectional & longitudinal • Prevalence of DSM-III-R/IV disorders (3 month prevalence) • 9, 11, 13 years of age + 3 years so up to 16 years of age {“accelerated design”/control for cohort effect} • Stage 1: Randomly selected sample for screening using externalizing items from the Child Behavioural Checklist + expanded questions on substance abuse using parent as informant • Stage 2: top 25% on screening + 1 in 10 of the rest invited to participate in structured interview using the Child and Adolescent Psychiatric Assessment (CAPA) using parent and child as informants • Response rate: • 96% of eligibles agreed to screening (n=3896) • 80% of eligibles agreed to interview (n=2086)

35. Great Smoky Mountains Study • Parent and/or child report (diagnosis, not impairment) • 20.3% any disorder • 11.9% any emotional or behavioural disorder • 6.8% any emotional disorder • 6.6% any behavioural disorder • 5.7% any anxiety disorder • 5.1% enuresis • 4.2% any tic disorders

36. Great Smoky Mountains Study • Approximately 1/3rd of children had more than 1 disorder (i.e., comorbidity) • Boys>girls for any psychiatric disorder primarily due to higher rates of behavioural disorders and enuresis (also higher co-morbidity of emotional and behavioural disorders in boys) • Children of the poorest families had higher rates of any disorders and every type except tic disorders, especially behavioural disorders (also co-morbidity) • Urban not higher than rural after controlling for income

37. Great Smoky Mountains Study • Decreasing with age: • ADHD, SAD, enuresis, encopresis, tics • Increasing with age: • Substance Use Disorders, panic, GAD • Girls only: Depression & social phobia

38. Impaired but undiagnosed • Angold et al., 1999 • Smoky Mountain data • 7.4% diagnosis + impairment • 11.5% diagnosis, not impaired • 14.2% impaired, no diagnosis • 3.6% parent-child relational problem • 1.4% siblings relational problems • 52% of specialty mental health service users did not meet diagnostic criteria for 29 DSM-III diagnoses

39. References • American Psychiatric Association (2012) DSM: History of the Manual. http://www.psychiatry.org/practice/dsm/dsm-history-of-the-manual • Angold A, Costello EJ (2009) Nosology and measurement in child and adolescent psychiatry. Journal of Child Psychology & Psychiatry 50(1-2): 9-15. • Aarons G et al (2001) Prevalence of adolescent substance use disorders across five sectors of care. J Am Acad Child Adolesc Psychiatry 40(4): 419-426. • Breton JJ B et al (1999) Quebec Child Mental Health Survey: Prevalence of DSM-III-R mental health disorders. J Child Psychol Psychiat 40(3): 375-384. • Coghill D, Sonuga-Barke E (2012) Annual research review: Categories versus dimensions in the classification and conceptualisations of child and adolescent mental disorders – implications of recent empirical study. Journal of Child Psychology & Psychiatry 53(5): 469-489. • Copeland W, Shanahan L, Costello EJ, Angold A (2011) Cumulative prevalence of psychiatric disorders by young adulthood: A prospective cohort analysis from the Great Smoky Mountains Study. JAACAP 50(3): 252-261. • Costello et al (2005) 10-year research update review: the epidemiology of child and adolescent psychiatric disorders: I. Methods and Public Health Burden. Journal of the American Academy of Child and Adolescent Psychiatry 44(10): 972-986. •  Costello et al (2006) 10-year research update review: the epidemiology of child and adolescent psychiatric disorders: II. Developmental Epidemiology Journal of the American Academy of Child and Adolescent Psychiatry 45(1): 8-25

40. References -2 • First M (2010) Paradigm shifts and the development of the diagnostic and statistical manual of mental disorders: Past experiences and future aspirations. Can Journal of Psychiatry 55(11): 692-700. • Garland A et al (2001) Prevalence of psychiatric disorders in youths across five sectors of care. J Am Acad Child Adolesc Psychiatry 40(4): 409-418. • Jensen A (1969) How much can we boost IQ and scholastic achievement. Harvard Educational Review 39(1) • Kessler R et al (2012) Severity of 12-month DSM-IV disorders in the national comorbidity survey replication adolescent supplement. Arch Gen Psychiatry 69(4): 381-389. • Kessler R et al (2012) Prevalence, persistence and sociodemographic correlates of DSM-IV disorders in the national comorbidity survey replication adolescent supplement. Arch Gen Psychiatry 69(4): 372-380. • WidigerT, Samuel D (2005) Diagnostic categories or dimensions? A question for the Diagnostic and Statistical Manual of Mental Disorders – Fifth Edition. Journal of Abnormal Psychology 114(4): 494-504.