This study sets out to test the hypothesis that parameters of heart rate variability, as a non-invasive measure of cardiovascular risk, can be improved by the addition of omega-3 fatty acids in euthymic bipolar patients with a low omega-3 index and reduced heart rate variability.

Inclusion Criteria:

1. Subjects must meet the DSM-IV criteria for bipolar disorders, in remission
2. Age: 18 - 65 years
3. Low omega-3 index (<5%)
4. SDNN < 60 msec
5. Subjects must have adequate fluency in German or English to complete baseline and follow-up interviews and fill out the Beck Depression Inventory
6. Stable psychotropic medication for at least 2 weeks
7. Subjects must be able to give written informed consent

Exclusion Criteria:

1. Subjects for whom the intake of omega-3 fatty acids is indicated according to recent treatment guidelines
2. Patients on Warfarin
3. Subjects with any acute and life-threatening condition, such as collapse and shock, acute myocardial infarction, stroke, embolism
4. Subjects with significant medical comorbidity
5. Pregnant subjects - due to any possible teratogenic effects of EPAX 6015 TG and corn oil, respectively, on the fetus - and breastfeeding subjects. In addition, women of childbearing potential who will not practice a medically accepted method of contraception will be excluded
6. Subjects who, in the investigator's judgement, pose a current significant suicidal or homicidal risk or patients who will not likely be able to comply with the study protocol
7. Subjects fulfilling the DSM-IV diagnostic criteria for current substance abuse