Efficacy of Omega-3 Fatty Acids on Borderline Personality Disorder

Inclusion Criteria: 1. Meet DSM-IV criteria for BPD assessed by the Structured Clinical Interview for DSM-IV Personality Disorders (SCID-II). 2. Clinical Global Impression of Severity for BDP \> 3. 3. Age between 18 and 65 years. 4. Be able to give informed consent for participation. 5. Place of residency compatible with the assistance to the center. 6. If woman, use of effective contraception. Exclusion Criteria: 1. Have a serious medical illness. 2. History of omacor® allergy. 3. Current diagnostic unipolar depression, bipolar disorder type I, Obsessive-Compulsive Disorder, schizophrenia and other psychotic disorders. 4. DIB-R \> 8. 5. Suicidal thinking that requires hospital admission. 6. Meet DSM-IV criteria for alcohol, benzodiazepine, opioid or psychostimulant dependence in the six months prior to trial entry. 7. Transaminase elevation within three times the upper limits of normality. 8. Treatment with stable doses of antidepressants or mood stabilizers for less than six weeks. 9. Treatment with stable doses of antipsychotics for more than 1 week in the last three months. 10. Have received electroconvulsive therapy for the six months prior to trial entry. 11. Have received DBT in the last 12 months prior to trial entry. 12. Are pregnant or nursing. 13. Have participated in any other investigational study in the last 6 months prior to trial entry. 14. Current treatment or expectation to start any treatment with drugs that may interact with the study.