Comorbidity in Autism Spectrum Disorder

Comorbidity in Autism Spectrum Disorders is difficult to assess due to a lack of instruments specifically designed for this purpose. This study attempted to describe the frequency of comorbid Intellectual Disability, Attention deficit/Hyperactivity disorder, Self-Injurious Behavior, Disruptive Mood Dysregulation disorder and Epilepsy in children diagnosed with autism. A sample of 28 children ranging in age from 6 to 12 with a primary diagnosis of Autism Spectrum Disorder was recruited from public and private psychiatric clinics in the city of Ardebil. Data were gathered using DSM-5 diagnostic criteria sets by two clinicians independently. Data were obtained through naturalistic observation, interviews with parents and other service providers, and by analyzing video-taped films of the children’s behaviors at home and at school. Inter-rater reliability was high. Findings revealed that the most common comorbid condition was intellectual disability seen in 53.57% of the children, followed by ADHD (42.85%), Disruptive Mood Dysregulation Disorder (32.14%), Self-Injurious Behavior (21.42) and Epilepsy (10.71%). The proportion of children with no diagnosis of comorbidity was 10.71%. The association of age at first referral with comorbidity was also examined. Findings revealed a later age of diagnosis for comorbid conditions than for conditions with only autism spectrum disorder, indicating that predominant comorbid conditions in Autism Spectrum Disorder might actually delay early diagnosis and intervention. The implications are that symptoms of autism may be overlooked when more familiar behaviors descriptive of these above-mentioned disorders are manifested.

Keywords:

autism , comorbidity , neurodevelopmental disorder , neurological impairment , irritability , self-injurious behavior