This study will investigate the relationships between subjective cognitive complaints, neurocognitive deficits, and work productivity in participants with Major Depressive Disorder (MDD), before and after 8 weeks of treatment with an antidepressant medication. Our hypothesis is that, in working participants with MDD of at least moderate severity, neurocognitive deficits will predict poorer work functioning and productivity.

Inclusion Criteria:

1. Clinical diagnosis of Major Depressive Disorder as per DSM-IV-TR
2. Current employment of at least 15 hours per week
3. Baseline score of 23 or greater on the Montgomery-Asberg Depression Rating Scale, indicating at least moderately severe depression
4. Baseline score of 6 or greater on the British Columbia Cognitive Complaints Inventory, indicating at least moderate subjective cognitive complaints
5. Competency to give informed consent

Exclusion Criteria:

1. Current receipt of short-term or long-term disability benefits from employer

2. Serious suicidal risks as judged by the investigators

3. Other DSM-IV-TR diagnoses:

   1. organic mental disorders
   2. active substance abuse/dependence, including alcohol
   3. schizophrenia, paranoid or delusional disorders, or other psychotic disorders
   4. (as primary diagnosis:) panic disorder, generalized anxiety disorder, obsessive-compulsive disorder, or post-traumatic stress disorder
   5. bipolar disorder
   6. bulimia nervosa or anorexia nervosa

4. Serious illness that is not stabilized, including cardiac, hepatic, renal, respiratory, endocrinologic, neurologic, or hematologic disease

5. Regular/current use of other psychotropic drugs and/or herbaceuticals

6. Use of fluoxetine within 5 weeks of Visit 1, monoamine oxidase inhibitors within 14 days of Visit 1, and other antidepressants within 7 days of Visit 1 (all to ensure adequate drug washouts prior to neurocognitive assessment)

7. Previous treatment with desvenlafaxine

8. Treatment-resistance in the current episode, as defined by failure (i.e., lack of clinically significant response) of 2 or more antidepressants given at therapeutic doses for at least 6 weeks

9. Any history of treatment with electroconvulsive therapy

10. Initiation of formal psychotherapy (e.g., cognitive-behavioural therapy or interpersonal psychotherapy) with 2 months of Visit 1, or plans to start such psychotherapy during this study

11. Current use of any other form of treatment for depression