Recent psychobiological studies indicate that pharmacotherapy could be useful for the treatment of personality disorders. In this paper, the results of clinical pharmacological studies are reviewed according to DSM-IV axis-II categorization, which classified the personality disorders into three clusters: A (paranoid, schizoid and schizotypal), B (antisocial, borderline, histrionic and narcissistic) and C (dependent, avoidant and obsessive-compulsive). Although few controlled studies have been conducted in cluster A personality disorder, low doses of antipsychotic drugs might be useful in these patients. Most studies have been carried out in cluster B, and especially in borderline personality disorder. Partial positive results have been obtained using neuroleptics, antidepressants, benzodiazepines (alprazolam) and antimaniac drugs. Finally, in cluster C, some isolated studies suggest a favourable clinical effect of antidepressants (especially SSRIs and venlafaxine) and benzodiazepines.