Design makes a difference: a meta-analysis of antidepressant response rates in placebo-controlled versus comparator trials in late-life depression.
OBJECTIVE
Qualitative reviews of late-life antidepressant clinical trials suggest that antidepressant response rates in comparator trials are higher than antidepressant response rates in placebo-controlled trials. No quantitative review has been conducted to test this hypothesis.


METHODS
A meta-analysis was conducted of all published articles in peer-reviewed journals from 1985 to the present to identify randomized clinical trials contrasting antidepressant pharmacotherapy to placebo or an active comparator in late-life depressed outpatients. Sixteen studies (nine comparator trials and seven placebo-controlled trials) were identified. Antidepressant response rates in both placebo-controlled and comparator trials were extracted and submitted for analysis using multilevel meta-analysis procedures.


RESULTS
The authors found significant variability in antidepressant response rates beyond chance. This variability decreased by 27% when the authors included study type in the model. As expected, antidepressant response rates in comparator trials were significantly higher (60%) than antidepressant response rates in placebo-controlled trials (46%).


CONCLUSIONS
Antidepressant response rates are higher in comparator trials as compared to placebo-controlled trials. These findings have important implications for combined medication and psychotherapy trials that use placebo-controlled medication conditions because the response rates from these conditions are likely to be lower than those from unblinded conditions.
Sneed
Joel R
JR
Department of Psychiatry, Columbia University, New York State Psychiatric Institute, 1051 Riverside Drive, New York, NY 10032, USA. js2627@columbia.edu
Rutherford
Bret R
BR
Rindskopf
David
D
Lane
David T
DT
Sackeim
Harold A
HA
Roose
Steven P
SP
D000367:Age Factors; D000368:Aged; D000928:Antidepressive Agents / Q000627:therapeutic use*; D003866:Depressive Disorder / Q000188:drug therapy*; D006801:Humans; D015233:Models, Statistical; D010919:Placebos; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D012107:Research Design; D016896:Treatment Outcome
D000928:Antidepressive Agents; D010919:Placebos