Mental disorders in five-year-old children with or without developmental delay: focus on ADHD.

Epidemiological studies of children and adolescents with intellectual disability have found 30 to 50% exhibiting clinically significant behavior problems. Few studies, however, have assessed young children, included a cognitively typical comparison group, assessed for specific disorders, and/or studied family correlates of diagnosis. We assessed 236 5-year-old children--95 with developmental delay (DD) and 141 with typical development--for clinical diagnoses using a structured interview. Every disorder assessed was more prevalent in the DD group. The percent of children meeting criteria for Attention Deficit Hyperactivity Disorder (ADHD) most highly differentiated the two groups (ratio = 3.21:1). There was high stability from externalizing behavior problems at age 3 to ADHD diagnoses at age 5 in both groups. In regression analyses, parenting stress at child age 3 related to later ADHD diagnosis in both groups and maternal scaffolding (sensitive teaching) also predicted ADHD in the DD group.