The Journal of clinical psychiatry
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A researcher must carefully balance the risk of 2 undesirable outcomes when designing a clinical trial: false-positive results (type I error) and false-negative results (type II error). In planning the study, careful attention is routinely paid to statistical power (i.e., the complement of type II error) and corresponding sample size requirements. However, Bonferroni-type alpha adjustments to protect against type I error for multiple tests are often resisted. Here, a simple strategy is described that adjusts alpha for multiple primary efficacy measures, yet maintains statistical power for each test. ⋯ The strategy described adjusts alpha for multiple primary efficacy measures and, in turn, modifies the sample size to maintain statistical power. Although the strategy is not novel, it is typically overlooked in psychopharmacology trials. The number of primary efficacy measures must be prespecified and carefully limited when a clinical trial protocol is prepared. If multiple tests are designated in the protocol, the alpha-level adjustment should be anticipated and incorporated in sample size calculations.
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of changing from typical to atypical antipsychotic drugs on subjective sleep quality in patients with schizophrenia in a Japanese population.
To investigate the effects of the atypical antipsychotic drugs risperidone, olanzapine, quetiapine, and perospirone on the subjective quality of sleep in patients with schizophrenia. ⋯ These results demonstrated that atypical antipsychotic drugs improved subjective quality of sleep in patients with schizophrenia compared with conventional antipsychotic drugs, suggesting that the marked potency of serotonin-2 receptor blockade in atypical antipsychotic drugs may be involved in the mechanism of this improvement. These improvements were correlated with improvement of negative symptoms.