[What are the Specific Characteristics of Clinical Trials for Neuropsychiatric Disorders?]

To increase medical standards, not only the establishment of therapeutic strategies to accumulate evidence for existing therapies but also the development of new therapies are required. In recent years, as a number of new drugs have been approved, treatment options for neuropsychiatric disorders have expanded. It is significant for clinicians to interpret the evidence adequately in order to select the optimal therapeutic method. This paper aims to describe the important points in interpreting the results of clinical trials, which involve direct evidence for efficacy and safety. There are several specific characteristics of clinical trials for neuropsychiatric disorders. As typical features, the following can be mentioned: 1) a high and variable response in placebo groups, 2) impact on the effect size of the baseline severity of disorders, 3) high dropout rates, and 4) biases related to subjective measures of clinical symptoms. In this paper, the key points to be evaluated in the results of clinical trials for neuropsychiatric disorders are discussed based on these features.