End of allotted time for subject recruiting.

This study will be a randomized controlled trial set in an outpatient clinic, involving patients with major depressive disorder, who will be treated with antidepressant therapy, which will be individually agreed upon by the subject and his or her physician. Patients will be randomized to receive either placebo or fish oil capsules containing eicosapentaenoic acid (EHA) and docosahexaenoic acid (DHA) in addition to their antidepressant medication. Subjects will complete a brief dietary and exercise habits survey at the beginning of the trial to take into account lifestyle factors that may be significant in symptom resolution. Their progress will be monitored over a period of twelve weeks, with standardized rating scales completed by subjects and treating physicians. At the end of the study, scores will be compared between groups to look for differences in timing and degree of symptom improvement to analyze whether improvement occurred faster in the group receiving essential fatty acids (EFAs) than in the one receiving placebo. The primary hypothesis is that supplementation of antidepressant therapy with omega-3 fatty acids will decrease the lag period between the start of therapy and the time of clinically significant symptom improvement. A secondary hypothesis is that the results of this study will be consistent with numerous previous studies showing improvement in symptom control in major depressive disorder when antidepressants are supplemented with omega-3 fatty acids.

Inclusion Criteria:

• Diagnosis of Major Depressive Disorder.
• Allowed comorbidities: Dysthymia, Anxiety Disorders.
• 18 years old or older.
• Males + Females.
• English-speaking.
• Women of reproductive age must be on adequate birth control, either oral contraceptives or using condoms or other barrier methods with spermicidal agents.
• Subjects may be undergoing psychotherapy, but must maintain current psychotherapy status. Must not start therapy if not already in therapy. If in therapy, must have received at least 6 sessions prior to entering the study.
• Subjects may continue taking herbals or supplements during the study, but they may not start any new herbals or supplements during the study.

Exclusion Criteria:

• 2 or more failed trials of antidepressants (adequate dose and duration, and documented).
• Substance dependence in the past 6 months.
• Current substance use or abuse (MJ, benzodiazepines, narcotics). If BZD use, patient must be tapered off and wait 1 month before being included in the trial.
• Psychosis.
• Bipolar Affective Disorder Type I, II or NOS.
• Pregnancy (current or planned).
• Unstable medical illness (pt has to be stable for at least 3 months, and may be excluded per investigator discretion).
• Dementia.
• Mental retardation.
• Traumatic Brain Injury.
• History of Stroke.
• History of seizure disorder.
• Electroconvulsive therapy within past 6 months.
• If, at the investigator's discretion, it is suspected that the subject will likely not comply with the study protocol.
• Imminent risk for suicide.