Differential responses to a single antidepressant in recurrent episodes of major depression.

OBJECTIVES: The study examined whether patients who responded to an antidepressant in one episode of depression responded to the same agent in a subsequent episode. It also sought to determine whether in a subsequent episode clinicians prescribed an antidepressant that had previously been effective. METHODS: Charts of inpatients with a diagnosis of major depression who were consecutively admitted to general hospital psychiatric wards were screened to determine whether the patients met the inclusion criteria of recurrent major depression and had responded to antidepressant therapy in a previous episode. Data were collected on type of treatment and treatment response for each episode. RESULTS: Fifty-nine patients met the inclusion criteria. Thirty-five of the patients (59.3 percent) were prescribed the same antidepressant in both the current and previous episodes. Of these, 20 patients responded and 15 did not. Of the 24 patients who did not receive the same antidepressant, 14 were attended by the same clinician in both treatment episodes. Nineteen of the 24 patients responded to a new antidepressant, and five did not. CONCLUSIONS: Patients with recurrent depression are often prescribed antidepressants other than those that were effective in previous treatment episodes. Use of a previously effective antidepressant may not increase the treatment response rate in a subsequent depressive episode.

Verbal learning by major depressive disorder patients during treatment with fluoxetine or amitriptyline.

After 1 week of a single-blind placebo period, and prior to being randomly assigned to receive treatment with either fluoxetine or amitriptyline, patients meeting strict criteria for a diagnosis of major depressive disorder were given an auditory verbal learning test of working memory, and a blood sample was drawn. After 3 weeks of drug treatment with either amitriptyline or fluoxetine, the patients' symptoms were evaluated, the verbal learning test was repeated, and a second blood sample was taken. The clinical evaluation, the verbal learning test and the blood drawing were repeated a third time 3 weeks after the second assessment. The amount of anticholinergic activity in the blood samples was measured by a competitive radioligand binding assay and expressed in atropine equivalents. Analyses of variance indicated that there were no significant differences at the predrug Assessment 1 between patients subsequently assigned to the fluoxetine group compared with those assigned to the amitriptyline group. At Assessments 2 and 3, the fluoxetine and the amitriptyline groups showed equal clinical improvement but patients receiving amitriptyline did not perform as well on the verbal learning task. Serum anticholinergic activity at Assessments 2 and 3 was considerably higher in the amitriptyline group. This supports the hypothesis that blockade of muscarinic receptors impairs working memory formation. Equally effective antidepressant drugs with little or no anticholinergic action, such as fluoxetine, may be preferable in patients with pre-existing mild cognitive impairment or in patients where a slight reduction in cognitive performance is not acceptable.