Interventional Study of Wellbutrin XL in Major Depressive Disorder With Atypical Features

Inclusion Criteria: * Age over 20 years * DSM-IV episode of MDD non-psychotic with atypical features characterized by mood reactivity and 2 or more symptoms of vegetative reversal (including overeating, oversleeping, severe fatigue or leaden paralysis, and a history of rejection sensitivity) * More than 19 score on the 29-item HAM-D * Ability to give informed consent Exclusion Criteria: * Bipolar depression * Any Axis I psychotic disorder * A history of suicide attempt, self-injurious action (excluding action with no intention of suicide) or overdosage (excluding apparently accidental overdosage) * Patients with more than 3-point score of suicide (HAM-D-29 Item 18) or patients whose C-SSRS assessment suggests that they are or have been at significant risk for harming themselves or have actually harmed themselves, or who, in the opinion of the investigator (sub-investigator), are at significant risk for harming self or others * A history of substance abuse in the previous 12 months * A history of hypersensitivity to bupropion or any other components of the preparations used in the study (Wellbutrin SR 150mg and Wellbutrin XL 300 mg tablets) * Serious or unstable medical disorders * Starting or terminating psychotherapy during the previous 12 weeks, * ECT treatment in the previous 3 months * Subject has a life time diagnosis of anorexia nervosa or bulimia within the past 12 month * Subject has a current or history of seizure disorder or brain injury (traumatic or disease-related) or any condition which predisposes to seizure- subject treated with other medications or treatment regimens that lower seizure threshold- subject undergoing abrupt discontinuation of alcohol or sedatives * Subjects that previously failed adequate courses of pharmacotherapy from two different classes of antidepressants or previous adequate course(s) of bupropion * Pregnancy or planning pregnancy - when a patient is in active reproductive age, he or she has to agree to use relevant contraception during the study * Patients on monoamine oxidase inhibitors (MAOIs) * Patients being treated with any other preparations containing bupropion as the incidence of seizures is dose dependent