Am J Psychiatry 1991; 148:197-203
Copyright © 1991 by American Psychiatric Association
Different types of placebo response in patients receiving antidepressants
FM Quitkin, PJ McGrath, JG Rabkin, JW Stewart, W Harrison, DC Ross, E Tricamo, J Fleiss, J Markowitz and DF Klein
Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY.
OBJECTIVE: The authors studied the responses of drug-treated patients in an
attempt to validate observations about abrupt and gradual improvements in
patients receiving placebo. Since previous data suggested that in the first
2 weeks of antidepressant treatment specific drug effects are unlikely, the
authors hypothesized that this improvement is a placebo effect. Therefore,
in the first 2 weeks of antidepressant treatment abrupt and gradual
improvements should have the characteristics of their placebo counterparts.
METHOD: The subjects were 263 patients in controlled antidepressant trials
lasting 6 weeks. RESULTS: The percentage of abrupt improvements that
occurred in the first 2 weeks was higher than that for gradual
improvements. Abrupt improvements during the first 2 weeks of drug
treatment were also less persistent than gradual improvements with drug and
no more persistent than improvements with placebo during the same period.
However, in weeks 3, 4, and 5, abrupt and gradual improvements with drug
were equally persistent and both were more persistent than abrupt
improvements with placebo. CONCLUSIONS: These data support the authors'
findings about placebo. Abrupt improvements during treatment with both drug
and placebo are more likely during the first 2 weeks of treatment and are
less likely to persist than gradual improvements. The fact that persistence
of abrupt improvements with drug in weeks 1 and 2 appears different from
that of gradual improvements but appears no different after week 3 suggests
that the mechanism of action of abrupt improvement with drug changes after
week 2.
