Clinical trials: bridging the gap between efficacy and effectiveness.

The need for clinical psychiatry research to provide practical information to clinicians, families, and consumers has led to the development of new approaches to clinical trials. Efficacy trials, the historical backbone of clinical research, have many shortcomings in delivering practical information to stakeholders. The 'effectiveness' or 'public-health' model of intervention research targets a diverse group of patients across multiple settings that are outside of academic medical centres, with study design and outcomes that are selected on the basis of their potential to produce clinically meaningful information. The National Institute of Mental Health has funded three such clinical trials in recent years, respectively targeting schizophrenia and Alzheimer's disease, depression, and bipolar disorder. Each of these studies has made a major impact, and provided new insights into the challenges of public health orientated trials in psychiatry. In this review, we describe the underlying principles and practical considerations in efficacy and effectiveness-orientated trials.