According to the authors, this was the largest study ever conducted assessing omega-3′s efficacy in treating major depression.
Initial analyses failed to clearly demonstrate the effectiveness of omega-3 for all patients taking part in the study. Other analyses, however, revealed that omega-3 improved depression symptoms in patients diagnosed with depression unaccompanied by an anxiety disorder.
Efficacy for these patients was comparable to that generally observed with conventional antidepressant treatment.
From October 2005 to January 2009, 432 male and female participants with major unipolar depression were recruited to take part in this randomized, double-blind study (neither patients nor researchers knew which capsules patients received).
For eight weeks, half of the participants took three capsules per day of OM3 Emotional Balance, a fish oil supplement containing high concentrations of eicosapentaenoic acid (EPA). The other half took three identical capsules of a placebo consisting of sunflower oil, flavored with a small quantity of fish oil.
In contrast with typical clinical studies designed to assess the effectiveness of antidepressants, this study included a high proportion of patients with complex and difficult-to-treat conditions, including patients resistant to conventional antidepressant treatments and patients also suffering from an anxiety disorder.
The aim was to assess the value of omega-3 supplementation in a group of individuals more like those treated in outpatient clinics.
Some 11 percent of men and 16 percent of women in Canada will suffer from major depression at some point in their lives, making this disorder a leading public health issue.
Depression, which is now the world’s fourth leading cause of morbidity and death, is expected to move up to the number two position by 2020.
“Despite significant progress in neuroscience over the past two decades, depression is difficult to treat,” Dr. Lespérance noted.
In view of the large number of patients who stop taking their medications in the first few months of treatment and those who refuse such treatment due to fear of stigmatization or side effects, it comes as no surprise that a large number of patients suffering from major depression use alternative treatments offered outside the health care system.
“Many of these treatments have not been adequately evaluated. That is why it was important to assess the efficacy of omega-3, one of the most popular alternative approaches,” he added.
Epidemiological and neurobiological studies have suggested that a relative deficit in polyunsaturated fatty acids of the omega-3 group may predispose individuals to psychological disorders such as depression.
Further, several preliminary clinical studies based on small numbers of patients have suggested that omega-3 supplements with high concentrations of EPA can help to reduce symptoms of depression among patients who fail to respond to an initial antidepressant treatment.
These studies have not, however, convinced the entire scientific community.
A broader study was needed to acquire further knowledge about the properties and efficacy of high-quality omega-3 supplements among patients suffering from major depression.
“We are proud that OM3 Emotional Balance, with its high concentration of EPA at unexcelled levels of purity delivers the dose of EPA needed for effective treatment,” said Claire Bertin, head pharmacist for isodisnatura, the laboratory producing the omega-3 supplement used in the study.
It is important to note that the study assessed use of omega-3 for eight weeks, at doses of 1050 mg of EPA and 150 mg of DHA each day. It is currently unknown whether taking higher doses or taking supplements over a longer period would yield different results.
These encouraging results show that use of EPA is effective among patients with unipolar depression unaccompanied by an anxiety disorder.
Additional research directly comparing omega-3 with conventional antidepressants could more clearly confirm their usefulness for patients suffering from depression.
The study was published in the online Journal of Clinical Psychiatry.