Recent studies have reported therapeutic benefit from the use of omega-3 fatty acids (EPA and DHA) as adjunctive treatment of depression.

The goal of this work is to assess the effectiveness and tolerability of dietary supplementation with omega-3 in the treatment of depressed patients.

Prospective, descriptive, observational study in a general psychiatry outpatient clinic. Consecutive inclusion of depressed patients started on dietary supplementation with omega-3 because of partial response to antidepressants and/or intolerance to high doses or combination of antidepressant drugs between January and May 2015. Sociodemographic variables, clinical data and information about tolerability were recorded. Clinical response to treatment over time was assessed at 4–6 months follow up using the 5-item CGI (Clinical Global Impression) scale.

We included 30 depressed patients started on omega-3. None of them reported side effects. Seventy-three percent of patients reported clinical improvement (40% much improvement, 33% some improvement). None of them got worse. We did not find association between clinical response and age, sex, type of depression nor duration of illness.

Despite the limitations of this study, our work support previous positive results on the use of omega-3 fatty acids (EPA and DHA) as adjunctive treatment of depression. Giving the safety of its use, clinicians might recommend omega-3 as adjunctive treatment of depression in cases with a partial response to antidepressants.