Placebo response in clinical trials with schizophrenia patients.

PURPOSE OF REVIEW

The magnitude of placebo response is an important factor in the outcome of clinical trials, in that excessive placebo response can obscure true drug-placebo differences. There is ample evidence of the impact of elevated placebo response in trials of major depression, but less intensive research has been done in the area of schizophrenia. We present a current review of placebo response in clinical trials of schizophrenia.

RECENT FINDINGS

The existing evidence suggests that placebo response in schizophrenia trials may be similar in magnitude, quality, and impact to that observed in depression trials, and has similarly increased over the past several years. We discuss factors influencing excessive placebo response during the conduct of clinical trials and how they may be managed to help minimize placebo response.

SUMMARY

There does not appear to be any single major factor contributing to the high levels of placebo response in schizophrenia clinical trials; therefore, a multipronged approach to minimizing excessive placebo response or its impact is recommended.