Clinical features of depressed patients who do and do not improve with placebo.

The substantial placebo response in depression confounds treatment decisions and the assessment of new therapies. Improvement with placebo occurs infrequently in patients with chronic depression and in those with pituitary-adrenocortical hyperfunction, but other consistent predictors of placebo response have not been detected. We divided 241 moderately to severely depressed patients who had received placebo on a double-blind basis for 3 to 6 weeks into responders (greater than or equal to 50% improvement in Hamilton depression score, final Hamilton depression score less than or equal to 10), extreme nonresponders (less than 25% improvement), and partial responders (all others). Improvement with placebo was associated with a relatively short illness, a precipitating event, depression of only moderate global severity, and a good response to previous antidepressant treatment. These observations suggest that depressed patients who do and do not recover with placebo have different conditions that have not yet been fully characterized.