What s in a name? Autism is a Syndrome. Autism Spectrum Disorders 6/30/2011. Autism Spectrum Disorder (ASD) vs Pervasive Developmental Disorder (PDD)

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1 Autism is a Syndrome A group of symptoms that tend to cluster together Share a common natural history Not necessarily a single etiology What s in a name? Autism Spectrum Disorder (ASD) vs Pervasive Developmental Disorder (PDD) A Distinction without a Difference? Autism Spectrum Disorders What are the Spectra in Autism Spectrum Disorders (ASD)? Deficits Diagnosis Reciprocal Social Language Cognitive Repetitive, Restricted, IS Autism + + +/- + Aspergers Many Autism Symptoms Poor/No Language ASD High Cognitive Function Good Social Skills PDD- NOS + +/- +/- +/- Poor Social Skills Fluent Language Low Cognitive Function Few Autism Symptoms 1

2 Among Developmental Disorders, Autism is relatively common With so many possible forms, how common is ASD? Medical Conditions ASD 0.6 % MR % Childhood Cancer 0.01 % Juvenile Diabetes 0.1 % Asthma 0.8 % Is There an Epidemic of Autism? Findings (/10,000) Best Estimate Prevalence of ASD Before 2000: 36.6/10,000 After 2000: 60/10,000 = 0.6% = 1 child in 165 E. Fombonne Pediatrics 2001;107:

3 Interpretations and Debates Why Four fold increase of ASD prevalence over 3 decades? Problems in Time Trends of fasd changes in case definition / case finding secular changes in age at diagnosis statistical power issues prevalence versus incidence rates Rate/10,00 00 Prevalence of autism in 32 surveys , Rate / Year of Publication Interpretations and Debates California CDER data : Department of Developmental Services, California

4 DSM III R Trends in Minnesota Individual with Disabilities Educational Act (IDEA) ICD 10 DSM IV Why Epidemiology of ASD Matters? Broad Definition of Epidemiology The study of the distribution and determinants of healthrelated statues in specified population and the application of this study to control of health (Dictionary of Epidemiology, 4 th edition) ) Narrow Definition of Epidemiology Counting Frequencies of Diseases 1) Incidence 2) Prevalence Gurney et al., 2003 Measures of Disease Occurrence Measures of Disease Occurrence (1) Incidence = # of new cases of the disease Sum of observed cases over time, across individuals (3) Prevalence= # of subjects with disease Population (sample size) 4

5 Impact of case definition on rates Interpretations and Debates N studies Mean rate Kanner s criteria Rutter s criteria DSM-III DSM-III-R DSM-IV / ICD Impact of Diagnostic Criteria (Northern Finland survey) Age N Population Dx Criteria Prevalence (/10,000) 000) ,216 Kanner , ,216 Autism: ICD10/DSM IV ASD: ICD Kielinen et al., 2000 Relative rates of AD and PDD NOS Study Definition for other PDD AD PDD NOS Ratio Fombonne & other PDDs Mazaubrun (1992) Fombonne et al other PDDs (1997) Powell et al. autism-spectrum (2000) disorders CDC (2000) PDD NOS Baird et al (2000) PDD NOS Lotter (1966) Brask (1970) Findings (/10,000) Study Definition for other PDD AD PDD NOS Behavior similar to autistic children Other psychoses or borderline psychotic Wing et al (1976) Socially impaired Hoshino et al (1982) Autistic mental retardation Burd et al (1987) Autistic-like 3.3 >7.8 Chakrabarti & PDD NOS Fombonne (2001) Cialdella & Marmelle (1989) Other forms of infantile psychosis Fombonne,

6 Findings (/10,000) Study Definition for other PDD AD PDD NOS Fombonne & Mazaubrun (1992) Fombonne et al (1997) Other PDDs Other PDDs Powell et al. (2000) ASD CDC (2000) PDD NOS Baird et al (2000) PDD NOS Chakrabati & Fombonne (2001) PDD NOS Fombonne, 2003 Interpretations and Debates Impact of Study Design (5 recent UK Studies) Study Baird et al (2007) Baird et al (2000) Chakarabarti & Fombonne (2001) Fombonne et al (2001) Taylor et al (1999) Location South East Thames South East Thames Size of Population Age 56, ,235 7 Staffordshire 15, England & Wales North Thames Method Special Need Screening + FU Assessment Early Screening + FU Identification Intense Screening + Assessment Prevalence (/10,000) , Household Survey , Administrative Records x10 Increase 10.1 Stafford survey : prevalence estimates N Rate / 10,000 95% CI Autism Asperger PDD NOS Rett CDD Sample of Recent surveys Autism PDDNOS + AS All PDD Age rate / M / F % IQ rate / M / F % IQ rate / 10,000 ratio normal 10,000 ratio normal 10,000 CDC, Baird et al, All PDD Chakrabarti & Fombonne

7 Incidence Studies of ASD: Incidence Studies of ASD Study Powell et al. (2000) Smeeth et al. (2004) Lauristern et al. (2004) Location Size of Population Age UK 178, UK, Wales, Ireland, Scotland 14,231,527 person-year Denmark 682, Method Record + Referral Review Record Review (GPRD database) Record Review (psychiatric registry) Incidence (/10,000) /10,000 person-yr 7.1 Study Honda et al. (2005) Williams et al. (2005) Barbaresi et al. (2005) Jick et al. (2006) Location Size of Population Age Japan 35,716 5 Autralia US - <=21 UK 440,332 person-yr 2-5 Method Early Screening+ FU assessment Record Review (Register) Medical Record Review Record Review (GPRD) Incidence (/10,000) Icasiano et al. (2004) Australia Record + Parent Interview 4.26/10,000 person-yr Kawamura et al. (2008) Japan 12,589 5 Early Screening+ FU assessment Present Epidemiological Research of ASD: Korean Prevalence Study of ASD Characteristic of Korean Autism Prevalence Study Total Population Study in a Single Community Utilization of Educational System Multiple Phase: Screening & Confirmatory Diagnoses Multiple Informants Screening: Teacher & Parents Utilization of Standardized Assessment for Confirmatory Diagnosis: ADI, ADOS, Intelligence Test Present Epidemiological Research of ASD: Korean Prevalence Study of ASD Low Risk Group Screening: Parents ASSQ upper 1 5%, Teacher ASSQ 10 High Risk Group1: Special Education Schools Low Risk Group: Regular Education Sh Schools) l) High Risk Group2: Disability Registry High Risk Group Screening: Open to everybody Confirmative Diagnoses : ADOS ADI R Intelligence Test Environmental Factors 7

8 Has Autism Become More Prevalent? Probably, yes Greater Awareness (better training?) Since Kanner, Bettelheim Clearer Diagnostic Criteria Especially since DSMIV/ICD 10 Broader Diagnostic Criteria Especially since DSMIV/ICD 10 Earlier Diagnosis Leads to better services? Increased environmental causes? Changes in Autism Epidemiology Prevalence INCREASED - definitely Incidence UNCHANGED - probably Debated 8