Abstract
The concept of personality disorder (PD) is more relevant in the clinical management of drug users than other approaches to personality assessment. A problem in diagnosis is separating behaviours inherent in the activity of drug misuse from true evidence of PD, especially the anti-social type (ASPD), and rating instruments vary in their ability to do this. Nevertheless, the available evidence suggests that approximately two-thirds of drug users in treatment have PD, with ASPD the most common. Studies have mainly been in opiate users, while the prevalence of PD may be lower across the range of drugs, and in non-treatment settings. PD has been found to be associated with a range of complications and adverse outcomes in drug use, including psychiatric problems, poor social functioning, dropout from treatment, and increased HIV risk behaviours and infection rates. Outcomes for ASPD individuals in methadone maintenance treatment appear reasonable, however, and it may be that early recourse to such treatment is the most practical option for many PD opiate users, a potential criticism being that this does not directly address the PD problems.