The aims of this study are 1) to examine the clinical utility of bupropion hydrochloride extended release (Wellbutrin XL®) in patients with Major Depressive Disorder (MDD) with atypical features; 2) to evaluate the tolerability of bupropion hydrochloride extended release (Wellbutrin XL®) in patients with MDD with atypical features.

Whether bupropion hydrochloride extended release (Wellbutrin XL®) improved atypical depressive symptoms has not been investigated. The investigators assumed that bupropion hydrochloride extended release (Wellbutrin XL®) will be effective and tolerable in the treatment of atypical depression in MDD patients.

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