This study will be carried our at the Mood Disorders Psychopharmacology Unit (MDPU), University Health Network (UHN), University of Toronto, with the approval of the Research Ethics Board (REB). Informed consent will be obtained from all subjects prior to study enrollment.50 male subjects between the age of 40 and 65 will be evaluated by the psychiatrist to assess whether each patient meets DSM-IV criteria for Major Depression using the MINI and to obtain their medical and psychiatric history. In addition, the SEX FX questionnaire (an instrument measuring sexual dysfunction) will be administered. Once each patient has signed the informed consent document, the research staff will assess the severity of depressive symptoms by administering the Hamilton Depression Rating Scale (HAM-D-17). A Symptom/Side Effect Rating Scale will also be administered to measure the presence and severity of side effects that each patient may be experiencing. Each patient will then have pulse, blood pressure, weight, height, waist and hip measurements taken to evaluate their health. Patients will be asked to provide blood (about 3 teaspoons) and urine (about 1/4 cup) samples for laboratory tests (bioavailable testosterone, LH, thyroid and prolactin). The blood samples will be obtained in the morning between 0800 and 1100 hr. Each patient will then be asked to complete a series of self-report measures including the SASS, the ADAM, and the Beck Depression Inventory.The 50 healthy controls will have a structured diagnostic interview (MINI) administered by the coordinator to obtain their psychiatric and medical history. They will undergo all laboratory tests required of the depressed population and all rating scales mentioned above will be completed with this population as well. Each patient is free to withdraw from the study at any time.