Modulating speed-accuracy strategies in major depression.

BACKGROUND: Depression is associated with deficits in cognitive flexibility. The role of general slowing in modulating more specific cognitive deficits is however unclear. AIM: We assessed how depression affects the capacity to strategically adapt behavior between harsh and prudent response modalities and how general and specific processes may contribute to performance deficits. METHODS: Patients suffering from major depression and age- and education-matched healthy controls were asked to randomly stress either speed or accuracy during perceptual decision-making. RESULTS: Diffusion models showed that patients with depression kept using a less conservative strategy after a trial with speed vs. accuracy instructions. Additionally, the depression group showed a slower rate of evidence accumulation as indicated by a generally lower drift rate. CONCLUSIONS: These data demonstrate that less efficient strategic regulation of behavior in depression is due not only to general slowing, but also to more specific deficits, such as a rigid dependence on past contextual instructions. Future studies should investigate the neuro-anatomical basis of this deficit.