As the second leading cause of disability worldwide, major depressive disorder has a profound effect on individuals and society. Treating this debilitating disorder is vital yet current treatments have severe side effects and inconsistent results.
A recent study conducted in California explored the influence of brain stimulation on mood in epilepsy patients. Epilepsy is often associated with depression as a comorbidity and thus provides a suitable model for studying treatments. Deep brain stimulation (DBS) has been investigated for selective neural network modulation in mood disorders but with limited success, with the effect of the treatment replying largely on spatial target selection.
Previous studies have established an increase in activity in a brain region called the lateral orbitofrontal cortex (OFC) in individuals with depression, which has been shown to normalise with treatment of antidepressants, displaying this area as a potential target for treating depression.
“THE SECOND LEADING CAUSE OF DISABILITY WORLDWIDE”
25 epileptic individuals with mild to severe depression were implanted with electrodes to stimulate the OFC whilst their mood was assessed. The results displayed a significant improvement in mood resulting from OFC stimulation, presenting the OFC as central to mood determination, and highlighting this area as a potential target for further research.
The stimulation appeared to have no effect on individuals who did not report previous low mood symptoms, which implies that the treatment of the OFC normalises the mood state and does not cause a non-specific mood increase. This means that stimulation would only affect individuals with abnormal OCF activity.
Depression displays substantial variation between individuals, with various brain areas being affected, and so whether these results would be observed on a widescale basis is yet to be determined. In addition, if multiple areas of the brain influence depressive disorders, targeting only one area may prove ineffective.
This study marks a breakthrough in support of the use of DBS in treating mood disorders and is a promising basis for further investigation.