Atypical antipsychotics are a new treatment option for patients with impaired impulse regulation as seen in Cluster B personality disorders. Preliminary data are available on the use of atypical antipsychotics especially in the treatment of impulsivity in borderline personality disorder. The aim of the present study is to investigate efficacy regarding impaired impulse regulation, different psychopathological symptoms and tolerability of quetiapine in a group of patients with Cluster B personality disorder.

Fifteen consecutive patients with a DSM-IV diagnosis of borderline, histrionic, or narcissistic personality disorder were treated for 8 weeks with open-label quetiapine at the dose of 400 mg/day. Patients were assessed at baseline, week 1, 2, 3, 4, 6, and week 8. The clinical efficacy and side effects were assessed using the following scales: Hamilton Scales for Depression (HAM-D) and Anxiety (HAMD-A), Beck-Depression Inventory (BDI), Barratt Impulsivity Scale version 10 (BIS-10), Brief Psychiatric Rating Scale (BPRS), and the Dosage Record and Treatment Emergent Symptom Scale (DOTES).

Twelve patients completed the study. Three patients (20%) dropped out due to noncompliance. A significant improvement was found for the scores of the following scales: BPRS (anxiety/depression subscale), HAM-D, and BDI. No significant result was found for impaired impulse regulation. Common adverse effects, possibly due to study medication, were mild-to-moderate somnolence, mouth dryness, agitation, nausea, and dizziness.

An 8 week open label treatment with 400mg quetiapine daily seems to improve depressive and anxiety, but not impulsivity symptoms in cluster-B personality disorders.