489. Laboratory measures of impulsivity in hospitalized adolescents with disruptive behavior disorders

Abstract

Disruptive behavior disorders (DBD) in DSM-IV include Conduct Disorder (CD) and Oppositional Defiant Disorder (ODD), both of which are characterized by impulsiveness, such as acting without thinking. We attempted to assess the external validity of a variety of computerized measures designed to prospectively measure “impulsiveness” as well as better characterize impulsiveness in DBD. We tested laboratory impulsiveness in adolescent psychiatric inpatients with clinically significant impulse control problems, all of whom met DSM-IV criteria for either CD or ODD. We compared their laboratory impulsiveness with that of adolescent controls. Compared to controls, adolescents with DBD emitted significantly increased rates of “false alarm” responses (to similar but nontarget stimuli) on a difficult variant of the Continuous Performance Test (CPT) with little difference in rates of “hits”. In addition, compared to the controls, patients with DBD displayed a significant inability to inhibit responses to a target “go” stimulus when presented with a “no-go” stimulus 150–350 milliseconds after “go” stimulus presentation. Moreover, in a free operant task which featured conditions of increasing reward (money) with the passage of time since the last response, the adolescents with DBD showed a relative inability to delay free-operant responses for reward. Differences between adolescents with DBD and controls in serotonin-related alleles will be examined in relation to diagnosis and performance on laboratory measures of impulsivity.