Early onset of antidepressant action of venlafaxine: pattern analysis in intent-to-treat patients

Pattern analysis has been used to distinguish between the true effect of an antidepressant and a placebo effect. The placebo effect constitutes clinical improvement that is attributable to the caregiver, treatment setting, or placebo substance. Pattern analysis allows identification of patients who have early persistent responses, delayed persistent responses, or no responses to a drug. In our study, we used this method to assess the onset and persistence of antidepressant activity of high daily doses of venlafaxine. Our analysis considered scores on the Global Improvement item of the Clinical Global Impressions scale for intent-to-treat patients in two double-masked, placebo-controlled studies of at least 6 weeks' duration. Dosages in both studies were rapidly titrated upward so patients received at least 200 mg/d within the first week of treatment. Improvement within the first 2 weeks was considered early, and improvement not followed by a relapse through the scheduled end of treatment was considered persistent. Significantly greater percentages of patients in the venlafaxine group (27% and 20% in study 1 and study 2, respectively) than in the placebo group (9% and 2%, respectively) had a clinically meaningful drug response within the first 2 weeks of treatment. This early response persisted for the duration of each trial. We concluded that venlafaxine in dosages of at least 200 mg/d demonstrates an early and persistent onset of efficacy compared with placebo.

Zalospirone in major depression: a placebo-controlled multicenter study

Compounds active at the serotonin (5-HT)1A receptor (mostly azapirones) have shown some evidence of antidepressant effect. We report here the results of an antidepressant trial with zalospirone, a novel cyclic imide with 5-HT1A partial agonist activity. Two hundred eighty-seven outpatients (mean age 44 years, 55% men, 45% nonfertile women) who met criteria for unipolar major depression with a minimum 21-item Hamilton Rating Scale for Depression (HAM-D) score of 20 were randomly assigned to receive 6 weeks of double-blind treatment with either placebo or one of three fixed doses of zalospirone (6, 15, or 45 mg/day), administered three times daily. The high dose (45 mg) of zalospirone produced a significant antidepressant effect compared with placebo from week 2 on with mean improvement (change from baseline) in HAM-D total score of 12.8 versus 8.4 (p < 0.05) at week 6. Clinical improvement with the high dose of zalospirone was consistent across all outcome measures, however, only in the observed cases and not the last-observation-carried-forward analyses. Improvement with the 6-mg or 15-mg doses was greater than that with placebo, but not significantly so, suggesting a dose-response effect. Although the 45-mg dose of zalospirone seemed to have significant antidepressant efficacy, it was not well tolerated. Dizziness and nausea were noted in almost half of the patients, and by week six, 51% of patients in the high-dose group had dropped out. Whether or not tolerance to this high dose might be improved by gradual drug titration, only future research can answer.