PREDICTION OF POSITIVE PLACEBO-RESPONSE AMONG CHRONIC-SCHIZOPHRENIC OUTPATIENTS

We undertook this study to determine whether predictors of positive pl acebo response in chronic schizophrenic outpatients could be identifie d. Twelve placebo responders and 33 placebo nonresponders who particip ated in a parallel-group, double-blind, 12-week clinical drug trial we re compared. No significant differences between the groups were found with regard to 16 anamnestic and symptom variables. To investigate fur ther which variables at baseline predicted positive placebo response, a stepwise linear regression model was created. Of the seven variables entered into the model, only high scores in the positive domain of th e Positive and Negative Syndrome Scale (delusions, unusual thought con tent, grandiosity, and suspiciousness/persecution) at baseline predict ed significantly positive placebo response (p = .0047). Because the on set of placebo response was gradual, the authors hypothesize that plac ebo response in chronic schizophrenia consists mainly of two ingredien ts: nonspecific psychotherapeutic effect caused by the several assessm ents carried out during the study, and regression toward the mean.