Electroconvulsive stimulation reverses anhedonia and cognitive impairments in rats exposed to chronic mild stress.

Electroconvulsive therapy remains the most effective treatment for depression including a fast onset of action. However, this therapeutic approach suffers from some potential drawbacks. In the acute phase this includes amnesia. Electroconvulsive stimulation (ECS) has previously been shown to reverse a depression-like state in the chronic mild stress model of depression (CMS), but the effect of ECS on cognition has not previously been investigated. In this study the CMS model was used to induce a depressive-like condition in rats. The study was designed to investigate the acute effect of ECS treatment on working memory and the chronic effect of repeated ECS treatments on depression-like behavior and working memory. The results indicated that, in the acute phase, ECS treatment induced a working memory deficit in healthy controls unexposed to stress, while repeated treatments reversed stress-induced decline in working memory, as well as recovering rats submitted to the CMS paradigm from the anhedonic-like state. Like in the clinical setting, a single ECS exposure was ineffective in inducing remission from a depression-like state.