Effects of Fish-oil on Mood and Cognitive Functions of Healthy Individuals

The Effects of Omega-3 Fatty Acids Dietary Supplements (Fish-oil) on Mood and Cognitive Functions of Healthy Individuals

The investigators recently found a positive effect of omega-3 supplements on cognitive function in healthy individuals after 4 weeks (J of Psychopharmacology 2009, 23: 831-840). The investigators hypothesize that 4 weeks consumption of omega-3 supplements in previously depressed individuals will positively affect their cognitive functions.

Secondly, low Heart Rate Variability (HRV) is a risk factor for cardiovascular disease. Some studies have found low HRV in patients with depression. No studies have investigated the effects of omega-3 fatty acid supplements on Heart Rate Variability in individuals with a history of depression. The investigators will test the hypotheses that omega-3 supplements lead to an improvement of heart rate variability indices in healthy volunteers with a history of depression.

Inclusion Criteria:

• Dutch-speaking men and women
• Normal weight (BMI between 18 and 27).
• Regular diets, not containing fish more than once a week.
• History of depression (at least one major depressive episode in the past).

Exclusion Criteria:

• Currently more than mildly depressed (BDI-II-NL score higher than 19, or score on the suicidality item of this scale higher than 1).
• Current or past psychosis
• Current substance abuse or past substance dependence
• Smoking or current use of soft drugs (current = month prior to study till completion)
• Any hard drug use (lifetime)
• More than 3 alcoholic consumptions/day

Participants will be asked to keep their dietary habits constant throughout the study.