Treating depression by stimulating the pleasure center

Even with the best of available treatments, over a third of patients with depression may not achieve a satisfactory antidepressant response. Deep brain stimulation (DBS), a form of targeted electrical stimulation in the brain via implanted electrodes, is now undergoing careful testing to determine whether it could play a role in the treatment of patients who have not sufficiently improved during more traditional forms of treatment.

A major challenge of this work is determining the best region of the brain to stimulate. Some researchers stimulate the subgenual prefrontal cortex, a brain region implicated in depressed mood states, while others stimulate a region called the “anterior limb of the internal capsule”, a nerve pathway that passes through the basal ganglia, a lower brain region. Physicians publishing a new report in Biological Psychiatry now describe findings related to the stimulation of the nucleus accumbens, a brain region the size of a hazelnut associated with reward and motivation that is implicated in processing pleasurable stimuli, sometimes referred to as the “pleasure center” of the brain. The inability to experience pleasure is a key symptom of depression and previous studies have shown that functioning of the nucleus accumbens is impaired in depressed individuals.

Bewernick and colleagues administered DBS treatment in ten patients with severe long-term depression who had not responded to multiple other antidepressant treatments, including psychotherapy, drug treatments and electroconvulsive treatment.