Antisocial personality disorder among drug abusers: Relations to other personality diagnoses and the five-factor model of personality

Antisocial personality disorder among drug abusers has been associated with poor drug abuse treatment outcome and greater human immunodeficiency virus infection risk compared with drug abusers without the disorder. Despite this, less is known about the personality trait dimensions of antisocial drug abusers, or about the prevalence of axis II comorbidity among this group. Similarly, little is known about the personality trait dimensions of antisocial drug abusers compared with those with axis II diagnoses other than antisocial or those with no personality diagnosis. The present study compared the personality traits of 203 outpatient opioid drug abusers categorized into either a pure antisocial group (i.e., antisocial diagnosis only), mixed antisocial group (i.e., antisocial plus another axis II diagnosis), other axis II group (i.e., axis II diagnosis other than antisocial), or a non-axis II group. Psychiatric diagnoses were made using a structured interview and personality traits of the four groups were compared using a self-report measure of the five-factor model of personality. As predicted, the mixed group was significantly more prone to neuroticism compared with the pure group, with higher scores on the vulnerability to stress and hostility facets. The mixed group also had a greater score on the neuroticism domain compared with the non-axis II group, with higher scores on five of the six facets. Significant differences were also found on agreeableness. The mixed group had lower scores on this domain (i.e., had higher interpersonal antagonism) compared with the non-axis II group. Somewhat surprisingly, the agreeableness score for the pure group was not significantly different from those of the remaining three groups. Also, no significant differences were found on the personality domains of extraversion, openness to experience, or conscientiousness among any of the four groups.