Comments on Expectancy, Cognition, and Antidepressant Response in Late Life Depression

Rutherford et al report a study examining the effects of cognitive impairment on expectancy in late life depression. Rutherford previously conducted a trial in which expectancy was prospectively manipulated as part of the experimental design. The authors demonstrated that expectancy increased in patients randomized to open label treatment and these patients experienced more rapid improvement than patients who received antidepressant treatment but thought they might receive placebo. In the current study, the authors took this a step further. They examined the effect of cognitive functioning on expectancy and then antidepressant response. Placebo response rates suggest expectancy appears to be an important factor in trials of new rapidly acting agents such as ketamine and brexanolone. The authors indicate that strategies to improve cognition might improve expectancy and depression outcome although this raises questions whether the etiology of the cognitive problems matters. These issues await further study.