Marmoset study gives insights into loss of pleasure in depression

December 4, 2018, University of Cambridge

Now, in a study involving marmosets, scientists at the University of Cambridge have identified the region of the brain that contributes to this phenomenon, and shown that the experimental antidepressant ketamine acts on this region, helping explain why this drug may prove effective at treating anhedonia.

Depression is a common and debilitating condition which is recognised as a leading cause of disability worldwide. A survey published in 2016 found that 3.3 out of every 100 UK adults had experienced depression in the week before being interviewed.

A key symptom of depression is anhedonia, typically defined as the loss of ability to experience pleasure. However, anhedonia also involves a lack of motivation and lack of excitement in anticipation of events. All these aspects have proven difficult to treat. One major issue slowing down progress in developing new treatments is that the brain mechanisms that give rise to anhedonia remain largely unknown.

"Imaging studies of depressed patients have given us a clue about some of the brain regions that may be involved in anhedonia, but we still don't know which of these regions is causally responsible," says Professor Angela Roberts from the Department of Physiology, Development and Neuroscience at the University of Cambridge.

"A second important issue is that anhedonia is multi-faceted—it goes beyond a loss of pleasure and can involve a lack of anticipation and motivation, and it's possible that these different aspects may have distinct underlying causes."

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