ATTENTION-DEFICIT HYPERACTIVITY DISORDER SUBTYPES AND COMORBID DISRUPTIVE BEHAVIOR DISORDERS IN A CHILD AND ADOLESCENT MENTAL-HEALTH CLINIC

Objective: To assess demographic characteristics and patterns of comor bid disruptive behaviour disorders (oppositional defiant disorder [ODD ] or conduct disorder [CD]) in subtypes of attention-deficit hyperacti vity disorder (ADHD). Method,, One hundred youths consecutively referr ed to a community child and adolescent mental health clinic and subseq uently diagnosed with ADHD by the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria were evaluated. The diagnosis was made by a child psychiatrist and was based on information from physici ans, parents, teachers, and diagnostic interviews with the youths and their parents. Results: The major findings were: 1) ADHD combined (C) type was diagnosed in 78% of the subjects, while 15% had inattentive ( I) type and 7% had hyperactive-impulsive (HI) type, and 2) patterns of comorbid disruptive behavioural disorders significantly differed amon g subtypes. Specifically subjects with the I type showed lower rates o f comorbid ODD than those with the C type (33% and 85%; P < 0.001) and HI type (33% and 100%; P = 0.005), subjects with the HI type displaye d a higher prevalence of CD than those with the I type (57% and 0%; P = 0.005) and C type (57% and 8%; P = 0.003). These results should be c onsidered tentative because the reliability of the diagnostic procedur es was not formally assessed and the number of subjects in the I and H I groups was small. Conclusion: ADHD subtypes showed significant diffe rences in the distribution of comorbid disruptive behaviour disorders. These results support the utility of ADHD subtypes but should be repl icated with a larger sample of I and HI type subjects using more rigor ous diagnostic methods.