Neuropsychological, psychophysiological, and personality assessment of DSM-IV clusters of personality disorders

Testing the construct validity of the three DSM-IV cluster groupings of personality disorders, in terms of neuropsychological, psychophysiological, and personality traits measures, was the purpose of this study. The results hardly confirm significant differences between B and C cluster groups in their neuropsychological functioning, but, instead, suggest that Cluster A could have some empirical validity based on executive prefrontal deficits (concept formation and sustained attention tasks) and clinical features. Similarly, no consistent differences among groups emerge when psychophysiological measures are compared. With regard to the Big-Five personality dimensions, the results also indicate that clusters may be more heterogeneous than the DSM-IV suggests. It appears, therefore, that the categorical division of DSM personality disorders into three discrete clusters may not be empirically justified.