Evaluating the impact of different control states in current psychiatric research design

SUMMARY A ‘control’ provides a point of clinical comparison for a new intervention, allowing researchers and clinicians to draw more confident conclusions about the effectiveness or potential harm of a given, often novel, therapy. Although this aspect of a trial's design provides the basis from which interventional impact is measured, it is often less closely examined. This commentary appraises a Cochrane Review that compares various controls in common use in modern psychiatric research and aims to characterise their effects on the outcomes of that research.