In general, we find evidence that investigators comply with scientific practice standards in preclinical non-animal and animal pharmacological research (13) and that neuropsychiatrists thoughtfully critique theories of disease (14, 15). Nevertheless, in drug development, we find frequent inadequate preclinical and initial clinical preparations for CTs, measurement errors, biases in interpretation and reporting, and other mistakes that undermine confidence in research on human subjects. Below, we discuss five factors that contribute to this situation (Fig. 1).
