Although no antidepressants are particularly effective as weight-loss aids, certain antidepressants can cause a small of weight loss. Some others, which do not tend to cause weight gain, would also be good selections for those seeking to lose weight as they would not interfere with your weight-loss efforts.
For the most part, the selective serotonin reuptake inhibitors -- Prozac (fluoxetine), Zoloft (sertraline), Paxil (paroxetine), Luvox (fluvoxamine), Celexa (citalopram) and Lexapro (escitalopram) -- do not affect weight, although Prozac may cause some weight loss and Paxil may cause weight gain.
Wellbutrin (bupropion) may occasionally be associated with either weight loss or gain, but it is generally weight neutral.
Effexor (venlafaxine), Cymbalta (duloxetine), Desyrel (trazodone) and Serzone (nefazodone) also do not affect weight.
Sources:
Moore, David P. and James W. Jefferson. Handbook of Medical Psychiatry. 2nd ed. Philadelphia: Mosby, 2004.
Vieweg, W. Victor R. et. al. "Psychotropic Drug Considerations in Depressed Patients with Metabolic Disturbances." The American Journal of Medicine 121.8 (2008) : 647-55.
