What is neuromodulation?
Neuromodulation means changing the activity of nerve cells by stimulating specific areas of the nervous system. The stimulation can be electrical, magnetic or chemical. Several neuromodulation techniques are evidence-based treatments for depression.
Medication travels through the whole body. Neuromodulation acts on specific brain circuits involved in mood. This lets it change brain activity where it matters for depression.
Neuromodulation includes several techniques: transcranial direct current stimulation (tDCS), transcranial magnetic stimulation (TMS), electroconvulsive therapy (ECT) and vagus nerve stimulation (VNS). Each one works differently. They all aim to bring activity in the brain areas affected by depression back into balance.
How neuromodulation works
Neuromodulation changes the electrical activity of brain cells in targeted areas. In depression, some brain areas are less active than usual and others are more active. Neuromodulation may help bring these circuits back into balance.
How it does this depends on the technique. tDCS uses a very mild electrical current that makes brain cells a little more or less likely to become active. It does not make them fire directly. Repeated sessions encourage neuroplasticity, which is the brain's ability to form and strengthen connections, so the changes can last.
For depression, a main target is the dorsolateral prefrontal cortex (DLPFC). Underactivity in this area is consistently observed in depression, and it plays a role in mood, planning and managing emotions.
Neuromodulation for depression
Depression affects several connected brain circuits, especially those involving the prefrontal cortex. Neuromodulation targets these circuits to help restore their usual function. For major depressive disorder, it offers a non-drug option, on its own or alongside medication.
Each technique involves different things. TMS has a large body of evidence and needs repeated clinic visits. ECT has remission rates commonly between 50% and 80%. It needs a general anesthetic and is used for severe depression. tDCS is designed for use at home, which brings neuromodulation home.
A tDCS treatment course starts with 5 sessions a week for the first 3 weeks, followed by continuation sessions. Benefits are cumulative and continue to build with ongoing sessions. tDCS can also be used alongside antidepressant medication.
