The purpose of this study is to determine the safety and effectiveness of s-adenosyl-l-methionine (SAMe) in treating major depression.

SAMe is a substance that is naturally produced by the body and is also sold as an over-the-counter drug. Although SAMe has not yet been approved for treating depression, evidence suggests that it has antidepressant properties. This study will determine whether SAMe is safe and effective in treating major depression.

This study will last 24 weeks. Participants will be randomly assigned to receive either the antidepressant escitalopram, SAMe, or placebo for 12 weeks. Participants who respond to treatment at the end of 12 weeks will stay on their regimen for an additional 12 weeks. Participants who do not respond to treatment will enter an open treatment phase where they will receive SAMe and escitalopram for 12 more weeks. Depression scales and self-report questionnaires will be used to assess participants. All participants will receive 3 months of follow-up care, including free medication and clinic visits as necessary.

Inclusion Criteria:

• Diagnosis of major depression
• Score of 25 or higher on the Inventory of Depressive Symptomatology (IDS-C) scale
• Score of higher than 2 on the Clinical Global Impression Improvement (CGI) scale
• Willing to use acceptable methods of contraception

Exclusion Criteria:

• Suicidal or homicidal
• Unstable illness, including cardiovascular, hepatic, renal, respiratory, endocrine, neurological, or hematological disease.
• Any of the following mental conditions: organic mental disorders; schizophrenia; delusional disorder; psychotic disorders; bipolar disorder; recent bereavement; severe borderline or antisocial personality disorder; panic disorder; or obsessive compulsive disorder
• Substance abuse, including alcohol abuse, within 6 months prior to study entry
• Uncontrolled seizure disorder, or a seizure disorder controlled with psychotropic anticonvulsants
• Psychotic features
• Current use of other psychotropic drugs
• Hypothyroidism
• Have taken 6 weeks or more of either escitalopram or SAMe during the current depressive episode
• Previous intolerance of SAMe or escitalopram
• Investigational psychotropic drugs within 1 year prior to study entry
• Have received two or more antidepressant therapies of adequate doses and duration and failed to respond
• Have received depression-focused psychotherapy
• Bleeding tissue disorder, low platelet counts, a history of GI bleeding, or use of medications that alter bleeding risk
• Long-term aspirin use
• Pregnancy

Adverse events for SAMe, escitalopram, and placebo, were reported during the 12 week double blind course of the study and during the 12-week open cross over phase that followed the acute treatment phase.