Duration of antidepressant trials: clinical and research implications.
The objective of our study was to demonstrate that additional antidepressant benefit occurs between weeks 4 and 6 in adult outpatients, even when dose is not increased. Response between weeks 4 and 6 was studied among depressed outpatients randomly assigned to imipramine, phenelzine, or placebo under double-blind conditions. Patients were selected for analysis only if they did not have a dose increase after the start of the fourth week of treatment (day 22). Eighty-eight patients met this condition. Conditional probability analysis was performed. Nonresponders to 4 weeks (28 days) of treatment had a significantly greater likelihood of responding by week 6 if they were on phenelzine rather than placebo. The same is probably true for patients on imipramine. In research and clinical care, 4 weeks is too short a trial of phenelzine to conclude a lack of efficacy. Four weeks is probably also too short a trial of imipramine.
Donovan
S J
SJ
Department of Therapeutics, New York State Psychiatric Institute, New York 10032.
Quitkin
F M
FM
Stewart
J W
JW
Ocepek-Welikson
K
K
Harrison
W
W
McGrath
P J
PJ
Nunes
E V
EV
Wager
S
S
Tricamo
E
E
D000328:Adult; D003866:Depressive Disorder / Q000188:drug therapy* / Q000523:psychology; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007099:Imipramine / Q000008:administration & dosage* / Q000009:adverse effects; D008297:Male; D010555:Personality Inventory; D010624:Phenelzine / Q000008:administration & dosage* / Q000009:adverse effects
D010624:Phenelzine; D007099:Imipramine