Comorbid psychiatric disorders complicate the course of ASDs by affecting detection, therapeutic interventions, prognosis and outcome. Despite the recent increase of studies on occurrence of medical and neurological conditions in persons with autism psychiatric comorbidity of ASD is less well examined and previous studies have reported diverse findings. The majority of previous studies did not investigate comorbidity as a primary question and most of them had methodological shortcomings, were not optimally designed and did not address sources of artefacts in detection of comorbidity. The better understand of comorbid psychiatric disorder in ASDs may facilitate more specific treatment potentially limiting negative outcomes.
Objectives: to examine comorbid psychiatric problems in a sample of children with ASD and their parents compared with an age and IQ matched control group and their parents.
ASD subjects participating in the Irish Autism Genetics Study were invited to participate. Inclusion criteria for the present study were diagnosis of autism based on the Autism Diagnostic Interview-Revised (ADI-R), a diagnosis of autism or autism spectrum disorder based on the Autism Diagnostic Observational Schedule (ADOS) and IQ score greater than 50. Cognitive assessment was based on assessment with the Leiter International Performance Scale-Revised (Leiter-R). Exclusion criteria for the study included known medical causes of autism, exposure to medications in utero known to cause autism, extreme prematurity, presence of the Fragile X anomaly or an abnormal karyotype. The age, gender and IQ matched control group was collected through Special Schools. Exclusion criteria for this group included children or adolescents with a known clinical diagnosis of ASD.
The Child Behavior Checklist 6-18 (CBCL/6-18) was used to assess behavioral/emotional problems in both groups. Parents reported their own psychological distress using the Brief Symptom Inventory (BSI).
Irish Health Service Executive’s Ethics Committee approved this study. Parents of the children had all signed informed consent forms prior to participation in the study.
There were 59 (88%) boys and 8 (12%) girls in the ASD group. Similarly, 57 (85%) of the control group were male and 10 (15%) were female. The groups did not differ significantly on mean age, mean IQ scores, gender, and parents mean age. Children with ASD in comparison to controls were significantly more depressed and withdrawn (CBCL/6-18 Anxious/depressed syndrome, Mean T score 63.99 vs. 54.27), and had more severe social (CBCL/6-18 Social problems syndrome, Mean T score 65.46 vs 55.09) and attention problems (CBCL/6-18 Attention problems syndrome, 77.10 vs 70.07). Almost half of the ASD group met CBCL DSM criteria for clinically significant ADHD (44.78 %) and anxiety (46.2%) problems. Parents of ASD children and controls did not significantly differ on any BSI symptom dimension.
High rates of clinically significant psychiatric problems were detected in ASD children, with anxiety and ADHD being the most frequently detected syndromes. Parental distress was not associated with the identification of psychological problems in children with ASD.