Table 1. Incidence Risk Ratio of Specific Diagnoses of Autism Spectrum Disorders in Relation to Individual and Parental Diagnosis of Obsessive-compulsive Disorder (OCD; 1994–2012).
| Prior Diagnosis of OCD in Parents a | Prior Diagnosis of OCD in Patients b | |||
|---|---|---|---|---|
| Specific Diagnosis of Autism Spectrum Disorder | Incidence Rate Ratio | 95% CI | Incidence Rate Ratio | 95% CI |
| Childhood Autism | 1.92 | 1.24–2.82 | 3.28 | 2.40–4.35 |
| Atypical Autism | 1.63 | 0.51–3.81 | 4.40 | 2.65–6.83 |
| Asperger's Syndrome | 2.06 | 1.38–2.94 | 5.45 | 4.54–6.46 |
| Other Pervasive Developmental Disorder | 2.05 | 1.10–3.45 | 9.39 | 7.50–11.59 |
| Unspecified Pervasive Developmental Disorder | 1.50 | 0.92–2.28 | 4.10 | 3.20–5.15 |
aMaternal or paternal diagnoses were categorized hierarchically as having a history of OCD, autism spectrum disorders or other psychiatric disorders. Estimates of relative risk were adjusted for calendar year, age, maternal and paternal age, sex, place of residence at time of birth and the interaction of age with sex
bEstimates of relative risk were adjusted for calendar year, age, maternal and paternal age, sex, parental history of psychiatric illness, first psychiatric hospital contact for any other disorder, place of residence at time of birth and the interaction of age with sex