This article reviews treatment options (augmentation, etc) for depressed patients with suboptimal clinical responses to an antidepressant. Approximately one third of depressed patients treated with antidepressants exhibit suboptimal or delayed clinical response to these medications. In such cases, alternative options include switching to another antidepressant or adding a second antidepressant. Augmentation strategies include addition of lithium carbonate, atypical antipsychotics, psychostimulants, thyroid hormone (triiodothyronine), pindolol, or buspirone. In approximately half of all antidepressant-resistant cases of major depressive disorder, controlled clinical trials have indicated that augmentation with lithium or thyroid hormone is effective. Pindolol therapy has been shown to accelerate clinical response in some but not all studies.