Patients were medication free for a minimum of 14 days except for benzodiazepines and 1 patient receiving buspirone hydrochloride (6 weeks in the case of fluoxetine hydrochloride and 1 month in the case of oral antipsychotic agents). The median number of days not taking each type of medication before PET was as follows: anticonvulsants and mood stabilizers1 (n = 5), 19 (range, 13-34 days); antidepressant, other2 (n = 7), 43 (range, 7-13 days); benzodiazepines (n = 17), 25 (range, 9-956 days); selective serotonin reuptake inhibitor, non-fluoxetine3 (n = 8), 26.5 (range, 9-461 days); and fluoxetine (n = 7), 64, (range, 41-984 days). Eighteen patients had no previous medication use. The following medications were taken by 1 patient each: lithium carbonate (terminated 43 days before PET), the monoamine oxidase inhibitor phenelzine sulfate (41 days), and levothyroxine sodium (16 days). The following medications were taken by 2 patients each: the antiparkinsonian drugs bromocriptine and pergolide mesylate (terminated 101 and 29 days before PET), risperdone (41 and 29 days), the typical antipsychotic agents haloperidol and thioridazine (44 and 30 days), the stimulants dextroamphetamine sulfate and methylphenidate hydrochloride (19 and 16 days), and electroconvulsive therapy (56 and 57 days). Three patients each took the following medications: buspirone hydrochloride (terminated 9, 17, and 44 days before PET), the tricyclic antidepressants clomipramine hydrochloride (n = 2) and nortriptyline hydrochloride (n = 1) (19, 82, and 956 days),1 divalproex sodium and carbamazepine,2 trazodone hydrochloride, venlafaxine hydrochloride, mirtazapine, nefazodone hydrochloride, bupropion hydrochloride,3 paroxetine, and sertraline hydrochloride.