Comorbid Behavioural Psychopathology and Autism Severity: Same or Different?

Autism spectrum disorders (ASDs) are now recognized to occur in ~1% of children and to be a major public health concern because of their early onset, lifelong persistence and the high levels of associated disability.  However, little is known about the associated psychopathology that may contribute to the level of disability. Delineating psychiatric comorbidity in ASDs is important because it may identify targets for specific intervention that could reduce overall impairment and improve quality of life and also signpost similar or different biological or environmental aetiological factors to those that are well recognised for psychiatric conditions. For example, several recent studies have indicated that common genetic factors might influence both ASD and ADHD symptoms.

Our recent epidemiological report (Simonoff et al., 2008; JAACAP) using a standardised, structured parental interview the Child and Adolescent Psychiatry Assessment (CAPA) found that two-thirds of 10- to 14-year old children with an ASD had at least one other psychiatric disorder that was causing additional functional impairment over and above that due to ASD, roughly six times the rate in the general population. Forty percent of the sample met criteria for two disorders; the most common being social anxiety disorder, ADHD and oppositional defiant disorder. Unlike for child psychiatric disorders in the absence of ASD there were few associations between putative risk factors and associated psychopathology. We concluded that comorbid psychiatric disorder in ASDs is common and frequently multiple and should be routinely evaluated in the clinical assessment of this group.