Impulsive behaviors in attention-deficit/hyperactivity disorder

The notion that difficulty in behavioral inhibition is the essential impairment of attention-deficit/hyperactivity disorder (AD/HD) has been prevailing. In this study, we assessed impulsive behaviors with regard to emotion, rule, and inattentiveness, by developing an impulsiveness scale and applying it for 103 parents of a boy with AD/HD. Exploratory factor analysis (EFA) of 18 items identified four primary factors: labeled emotion expression, social rule, rule in conversation, and inattentiveness. A covariance structural analysis was performed to extract response bias from latent constructs, and the fitness of the model was examined. In the finally adopted model on impulsive behaviors, the four factors extracted in EFA was explained by two independent second-order latent variables: labeled general impulsivity and cognitive impairment. Cognitive impairment significantly influenced on inattentiveness only, while general impulsivity on all the four factors. Furthermore, the scores of primary four factors were compared between two groups of a normal class group (n = 20) and three AD/HD subtypes:combined type (n = 37), predominantly hyperactive-impulsive type (n = 14), and predominantly inattentive type (n = 18). The results suggest differences in impulsive behaviors among the AD/HD subtypes.