Treatment Resistant Depression and Obstructive Sleep Apnea, Effect of Continuous Positive Airway Pressure (CPAP)

Inclusion Criteria: * Patients with TRD. * Males and females between the ages of 18 and 65 years who agree to take part and sign the Informed Consent will be invited to participate in the study. * Patients with co-morbid Dysthymic Disorder, Generalized Anxiety Disorder or Social Anxiety Disorder may be included in the study. Exclusion Criteria: * Patients with uncontrolled medical illnesses will not be permitted to participate. * Patients with a history of current or Bipolar Disorder, Schizophrenia, Panic Disorder, Obsessive-Compulsive Disorder or Anorexia Nervosa. * Head injury patients resulting in loss of consciousness for more than 10 minutes. * Patients with epilepsy or severe personality disorders who, at the judgment of the investigators, are not appropriate candidates for the study, will be excluded. * Patients who do not have the mental or physical capacity to apply the CPAP interface and to plug in and switch on an auto CPAP unit at home will be excluded. * Blind and/or deaf patients will be excluded. * Patients who initially decline an offer of CPAP treatment for OSA, and those who prefer conservative treatment options (weight loss, avoidance of alcohol and sedatives) will be excluded. * Patients with severe claustrophobia, who cannot tolerate any CPAP interface, will be excluded.