ABSTRACT: BACKGROUND:Drugs are widely used in borderline personality disorder (BPD) treatment, chosen because of properties known from other psychiatric disorders ("off-label use"), mostly targeting affective or impulsive symptom clusters. OBJECTIVES:To assess the effects of drug treatment in BPD patients. SEARCH STRATEGY:We searched bibliographic databases according to the Cochrane Developmental, Psychosocial and Learning Problems Group strategy up to September 2009, reference lists of articles, and contacted researchers in the field. SELECTION CRITERIA:Randomised studies comparing drug versus placebo, or drug versus drug(s) in BPD patients. Outcomes included total BPD severity, distinct BPD symptom facets according to DSM-IV criteria, associated psychopathology not specific to BPD, attrition and adverse effects. DATA COLLECTION AND ANALYSIS:Two authors selected trials, assessed quality and extracted data, independently. MAIN RESULTS:Twenty-eight trials involving a total of 1742 trial participants were included. First-generation antipsychotics (flupenthixol decanoate, haloperidol, thiothixene); second-generation antipsychotics (aripirazole, olanzapine, ziprasidone), mood stabilisers (carbamazepine, valproate semisodium, lamotrigine, topiramate), antidepressants (amitriptyline, fluoxetine, fluvoxamine, phenelzine sulfate, mianserin), and dietary supplementation (omega-3 fatty acid) were tested. First-generation antipsychotics were subject to older trials, whereas recent studies focussed on second-generation antipsychotics and mood stabilisers. Data were sparse for individual comparisons, indicating marginal effects for first-generation antipsychotics and antidepressants.The findings were suggestive in supporting the use of second-generation antipsychotics, mood stabilisers, and omega-3 fatty acids, but require replication, since most effect estimates were based on single studies. The long-term use of these drugs has not been assessed.Adverse event data were scarce, except for olanzapine. There was a possible increase in self-harming behaviour, significant weight gain, sedation and changes in haemogram parameters with olanzapine. A significant decrease in body weight was observed with topiramate treatment. All drugs were well tolerated in terms of attrition.Direct drug comparisons comprised two first-generation antipsychotics (loxapine versus chlorpromazine), first-generation antipsychotic against antidepressant (haloperidol versus amitriptyline; haloperidol versus phenelzine sulfate), and second-generation antipsychotic against antidepressant (olanzapine versus fluoxetine). Data indicated better outcomes for phenelzine sulfate but no significant differences in the other comparisons, except olanzapine which showed more weight gain and sedation than fluoxetine. The only trial testing single versus combined drug treatment (olanzapine versus olanzapine plus fluoxetine; fluoxetine versus fluoxetine plus olanzapine) yielded no significant differences in outcomes. AUTHORS' CONCLUSIONS:The available evidence indicates some beneficial effects with second-generation antipsychotics, mood stabilisers, and dietary supplementation by omega-3 fatty acids. However, these are mostly based on single study effect estimates. Antidepressants are not widely supported for BPD treatment, but may be helpful in the presence of comorbid conditions. Total BPD severity was not significantly influenced by any drug. No promising results are available for the core BPD symptoms of chronic feelings of emptiness, identity disturbance and abandonment. Conclusions have to be drawn carefully in the light of several limitations of the RCT evidence that constrain applicability to everyday clinical settings (among others, patients' characteristics and duration of interventions and observation periods).