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.