The purposes of the study are to: 1) evaluate the short-term efficacy and safety of modafinil in atypical depression; and 2) to evaluate the efficacy of modafinil in preventing relapse of atypical depression. The hypothesis is that modafinil is safe and effective in the treatment of atypical depression.

This study on the safety and efficacy of modafinil on atypical depression has an initial 12-week open label treatment period with modafinil that is followed by a 12-week double-blind, randomized parallel treatment period with either modafinil or matching placebo. Patients who demonstrate at least minimal improvement after 12 weeks are randomly assigned to either continuing treatment at their current dose or switched to matching placebo for 12 weeks.

Inclusion Criteria:

• adults 18-65 years of age
• DSM-IV criteria for major depressive episode with atypical features as assessed by the Atypical Depression Diagnostic Scale
• minimum score of 18 on the Hamilton Depression Scale (29-item version) at baseline
• baseline Clinical Global Impressions Severity score of 4 or more
• written informed consent
• negative serum pregnancy test for women of childbearing potential

Exclusion Criteria:

• any current primary DSM-IV Axis I disorder other than depression
• history of DSM-IV diagnosis of bipolar I disorder, schizophrenia or other psychotic disorder, mental retardation or other pervasive developmental disorder, or cognitive disorder due to a general medical condition
• history of substance abuse or dependence within the last 3 months
• suicide risk or serious suicide attempt with the last year
• clinically significant medical condition or laboratory or EKG abnormality
• history of non-response to three prior adequate trials of antidepressants
• women of childbearing potential who are unwilling to practice an acceptable method of contraception
• history of hypersensitivity to modafinil
• use of an investigational medication within the last 28 days
• use of antidepressant medication with 28 days of screening