Inhibition and executive functioning in Type A and ADHD boys

The present study was aimed at clarifying the standing of Type A behavior, as measured by behavioral observations, relative to Attention Deficit Hyperactivity Disorder (ADHD), using measures of inhibitory control and executive functioning. The study sample included 20 boys exhibiting Type A behavior, 21 boys exhibiting Type B behavior and 14 boys diagnosed with ADHD, ranging in age from 7 to 12 years. The results of the present study showed that the Type A children differed from Type B children on two time-related variables, response latency and reaction time, in accordance with the view of Type As as time-urgent and impatient. Furthermore, in comparisons with the ADHD group, the Type A boys were found to be superior on several performance tasks, such as Go/no-go omissions, time reproduction, story recall and memory for sequences of hand movements, although similarities between Type A and ADHD boys were evidenced in terms of response latency and reaction time. In other words, although Type A boys were similar to ADHD boys in terms of overt displays of time-urgency and impatience, Type As do not display deficits with regard to executive functioning, of the kind often found when ADHD children are compared with normal controls. It may thereby be concluded that Type A behavior and hyperactivity/ADHD appear to be well differentiated except with regard to what may be interpreted as impatience. Speculations concerning differing origins of overtly similar characteristics of Type A behavior and ADHD should be considered in future research.