Objectives: To use K-SADS variables to study AI symptoms in children with ASD and children with BD thus delineating a domain of affective instability.
Methods: Children between 7 and 13 years with either DSM-IV ASD or BD, recruited for separate studies, received assessments including: Kiddie-Schedule for Affective Disorders and Schizophrenia (K-SADS), the Autism Diagnostic Interview (ADI-R), and the DSM-IV Asperger’s/Autism Checklist. Nineteen symptoms from the K-SADS were selected as representative of AI based on face validity. The ASD and BD groups were compared for the frequency of these AI symptoms.
Results: As expected, K-SADS symptoms of AI were more prevalent in the BD group. However, a subset of the ASD group also demonstrated a high frequency of AI symptoms. A cluster of eight symptoms displaying the greatest overlap between the two groups including acts before thinking, distractibility, depressed affect, grandiosity, inappropriate affect, decreased sleep, elated mood, and flight of ideas had an average frequency of 47% in the BD group, 26% in the ASD group, and 3% in the control group. Symptoms of AI were extreme enough in 13% of children with ASD to warrant a secondary lifetime diagnosis of BD.
Conclusions: A subset of children with ASD has significant AI resembling BD. Biomarker research may help identify overlapping etiopathogenesis of AI across DSM disorders.