Inclusion Criteria:

1. male or female outpatients 18-65 years old
2. currently taking fluoxetine, sertraline, paroxetine, citalopram, or escitalopram at a stable dosage within the ranges specified for 1 month or longer required dosage range: (Prozac (fluoxetine) 20-80 mg/day; Celexa (citalopram) 20-60 mg/day; Lexapro (escitalopram) 10-30 mg/day; Zoloft (sertraline) 50-200 mg/day; Paxil (paroxetine) 20-60 mg/day; Paxil CR (paroxetine CR) 25-75 mg/day

3. Currently responding to the SSRI antidepressant treatment, as indicated by

   • a score of 15 or less on the HDRS 24 item at screening and baseline, and (b) CGI-Severity score of 2 or less at baseline
4. Meets DSM-IV criteria for Substance-Induced Sexual Dysfunction, with impairment of desire, arousal, or orgasm
5. Are currently involved in an intimate relationship which includes sexual contact
6. agree to use double-barrier contraception during sexual intercourse during the course of the study (women only)
7. Agree to the study team contacting the physician who prescribe their SSRI medication to inform them of their participation in the current study

Exclusion Criteria:

1. Patients with a DSM-IV diagnosis of Delirium, Dementia, and Amnestic, and other Cognitive Disorders,
2. Patients with a principal diagnosis meeting DSM-IV criteria for: Bipolar Disorder or cyclothymia, Schizophrenia, Delusional (Paranoid) Disorders and Psychotic Disorders Not Otherwise Specified, or Anorexia Nervosa or Bulimia,
3. Patients who, within the past 6 months, met DSM-IV criteria for abuse of or dependence on any drug, including alcohol,

4. Patients who would pose a serious risk for suicide during the course of the study, as evidenced by one of the following:

   • report of having a specific plan for killing themselves,
   • a score of 3 or higher on the Hamilton Depression Rating Scale item 3 as rated by the study doctor at the first visit, (indicative of active suicidal thoughts or behaviors), or
   • a suicide attempt within the past 6 months,
5. Patients with a history of medical conditions or procedures which may cause sexual dysfunction, including: peripheral vascular disease, radical prostatectomy, trans-urethral resection of the prostate [TURP], or spinal cord injury.
6. History of sexual dysfunction predating onset of depression and/or initiation of antidepressant therapy,
7. Patients receiving any other treatment for sexual dysfunction, including sex therapy
8. Pregnant or nursing women.
9. Patients with unstable or life-threatening medical conditions, such as uncontrolled hypertension, diabetes, or hypothyroidism, acute infections, pneumonia, severe renal or hepatic impairment.
10. Patients with any the following: retinal disease, sleep apnea, or narcolepsy.
11. Patients taking dopamine agonist medication.

12. Patients taking medications that are

    • associated with orthostatic hypotension, such as tricyclic antidepressants, MAO Inhibitors, and alpha1 antagonists
    • CYP1A2 inhibitors, such as fluoroquinolones, fluvoxamine, cimetidine
    • SSRI medication used cyclically for PMDD
13. Patients who do not expect to have regular sexual contact with another person over the next 13 weeks.
14. Patients with a DSM-IV diagnosis of Pathological Gambling