Deep Brain Stimulation against Depression

photo: x-ray of a skull

The doctors implanted electrodes in
the nucleus accumbens of their
patients; © University of Bonn

For the purpose of this study, they implanted electrodes in what is known as the nucleus accumbens. That is an important part of the 'reward system' which ensures that we remember good experiences and puts us in a state of pleasant anticipation. Inactivity and the inability to experience pleasure are two important signs of depression.

A total of ten patients with very severe depression participated in the study. Initial effects could sometimes be seen just after a few days. 'Thus, inter alia we observed increasing activity of the patients,' Professor Thomas E. Schlaepfer from the Bonn Clinic of Psychiatry and Psychotherapy explains. 'This was so successful that some of them were even able to work again, after having been incapacitated for many years. None of our patients had ever responded to any other therapy to a comparable extent before.'

Five patients' well-being improved considerably and in a sustained fashion. Even after a year, the stimulation of the nucleus accumbens still had the same efficacy as at the beginning of the study.

But what is the exact effect of the stimulation of the nucleus accumbens? 'We were able to show using functional brain imaging methods that the stimulation changes metabolic rates of different areas of the brain,' Thomas Schlaepfer says. 'What is very important is that the metabolic changes do not just affect the nucleus accumbens itself but also other regions of the limbic system, where the brain processes emotions and that are known to be dysfunctional in depression.

Due to the small number of patients in this and similar studies, the scientists warn against exaggerated hopes. 'However, our study definitely shows that deep brain stimulation can help some patients with extremely severe forms of depression,' Thomas Schlaepfer stresses.; Source: University of Bonn