What next? A review of pharmacologic strategies for treatment resistant depression.

When an antidepressant fails to help a depressed patient, clinicians are faced with the daunting task of choosing the next treatment. Several pharmacologic and nonpharmacologic strategies exist, but the evidence available to help clinicians decide which treatment will be most effective is limited. To help clinicians evaluate the literature on treatment resistant depression (TRD), we critically review several selected pharmacologic strategies.