A twin study of inattentive, aggressive, and anxious/depressed behaviors

Objective: To estimate genetic, environmental, and rater contrast influences on parental report of Attention Problems (AP), Aggressive (Agg), and Anxious/Depressed (AxD) behaviors of 492 twin pairs assessed with the Child Behavior Checklist. Method: A parent (92% mothers) of twins aged 8 to 12 years completed the Child Behavior Checklist. Genetic, shared and unique environmental, and rater bias effects were estimated for the AP, Agg, and AxD syndromes. Data on boys and girls were analyzed separately. Results were compared to prior research on related DSM disorders. Results: Estimates of genetic influences on AP (60%-68%), Agg (70%-77%), and AxD (61%-65%) were high for both sexes, but lower for AP than prior findings using DSM attention-deficit hyperactivity disorder (ADHD). However, unlike equivalent analyses of DSM ADHD based on parental report, there was no evidence of rater bias. Conclusions: Estimates of genetic influence on these common child psychopathological domains were high. There was no evidence of rater contrast effects. These findings have implications for diagnosis, particularly when assessing families with multiple children.