Randomised double-blind placebo-controlled trial of fish oil in the treatment of depression.

Converging evidence suggests that omega-3 polyunsaturated fatty acids have aetiological importance in depression. To determine the effect of adding fish oil to existing therapy in participants who were being treated for depression in a community setting, 77 participants were randomly assigned to receive 8 g of either fish or olive oil per day in addition to their existing therapy. Fifty-nine (77%) participants completed 12 weeks of treatment. Dietary, biochemical and lifestyle factors were measured throughout the study. Mood was assessed using the Short Form Hamilton Depression Rating Scale (HDRS-SF) and the Beck Depression Inventory II. Sample size calculations were based on the HDRS-SF. Intention-to-treat and per protocol analyses were carried out using residual maximum likelihood. There was no evidence that fish oil improved mood when compared to the placebo oil, despite an increase in circulating omega-3 polyunsaturated fatty acids. However, mood improved significantly in both groups within the first 2 weeks of the study (P<0.001) and this improvement was sustained throughout. In conclusion, fish oil was no more effective than the control as an add-on therapy for depression in this setting.

Dietary supplement use in people being treated for depression.

The use of dietary supplements has increased over the past 10 years, with up to 50% of adults being reported to have taken dietary supplements. The types of supplements taken are often related to physical morbidities. However, information about their use in combination with prescription drugs is lacking. In particular, there is little information on the use of supplements by people with depression. Our aim was to examine the use of dietary supplements by people being treated for depression. Seventy-two participants who were being treated for depression in the community were recruited for a clinical trial to determine the effect of fish oil on mood in the treatment of depression. The results of the primary analysis are reported elsewhere. Exclusion criteria included any co-existing psychiatric disorder (except anxiety disorders), blood clotting disorders, unstable medical conditions, and those taking fish oil supplements. Demographic information, details about the participants' depression and current therapies, use of dietary and herbal supplements in the previous 12 months, and physical activity data were collected at baseline. Characteristics of supplement users were compared with those of non-users using either chi-square or Mann-Whitney U tests. Forty-five (63%) of 72 participants who provided dietary supplement information had taken at least one dietary supplement within the previous 12 months. On average, supplement users were found to have taken 2.8 (SD=1.56) dietary supplements during the assessment period. Women were more likely to be taking supplements than men (P<0.001). In conclusion, the use of dietary supplements is common among people being treated for depression. This has important implications for clinical practice as little is known about supplement-drug interactions.