Deep Brain Stimulation (DBS)
Small electrodes are implanted into the brain to stimulate regions that are too deep to reach by stimulating the scalp. DBS is already approved for the treatment of Parkinson’s disease, and is under study for the treatment of severe and treatment resistant OCD and major depression.
Electroconvulsive Therapy (ECT)
ECT has been modernized substantially since it was first introduced some 70 years ago. ECT remains the most effective and rapidly acting treatment for severe medication resistant depression and other disorders. While ECT is the “gold standard,” current research is pushing the envelope to create a new standard, one that does not carry the same side effect burden as ECT. While ECT has already come a long way, the ECT of the future may be very different from the ECT of today. It will likely be performed more focally and precisely. We may use entirely new ways of inducing the seizure, with different types of electricity or with magnetic fields (see MST above).
Magnetic Seizure Therapy (MST)
MST uses TMS (see below) to perform a more focused form of convulsive therapy. ECT is highly effective but carries a risk of serious side effects such as amnesia or memory loss. MST takes advantage of the fact that magnetic fields can be focused. MST targets the stimulation in the prefrontal cortex (a region of the brain thought to be critical for antidepressant response), and limits the degree to which it spreads to the hippocampus (a region of the brain important for memory). MST holds the promise of retaining the efficacy of ECT, but without its side effect burden. If MST is proven effective, it could represent a breakthrough in the way that our most severe psychiatric disorders are treated.
Transcranial Direct-Current Stimulation (TDCS)
Early studies in Britain, in the 1960's, suggested that transcranial direct current stimulation might be effective in treating depression. Recent studies on small groups of patients suffering from depression showed promising results.
This blinded, sham-controlled, cross over trial builds upon these recent studies in extending the period of stimulation with tDCS from two weeks to possibly four weeks. If successful, tDCS could represent a safe and cheap alternative that could reach communities with less access to technological advancements.
Transcranial Magnetic Stimulation (TMS)
TMS uses magnetic fields that are applied to
the head with a compact and portable electromagnetic coil. These
magnetic fields are turned on and off very rapidly. This fluctuation in
the field induces a small electrical stimulation in the brain that
stimulates the neurons and causes them to fire. This stimulation
releases neurotransmitters in the brain, and modulates the firing rate
of the circuit. Depending on the frequency of stimulation, TMS can
either excite or inhibit brain function. TMS can be focused to
small regions of the brain (0.5 cm), allowing us to target specific
brain structures. TMS has been approved by the FDA for the treatment of
major depression that has failed to respond to an adequate trial of
antidepressant medication. A significant number of clinical trials also
show promise in treating schizophrenia, neurorehabilition and recovery
of function following stroke, among other conditions.
to watch a video of Dr. Lisanby discussing TMS.
Vagus Nerve Stimulation (VNS)
VNS is commonly called the “pacemaker for the brain.” An electrical device like a pacemaker is implanted in the chest. Electrical leads are connected to the vagus nerve in the neck. The vagus nerve sends impulses to the brain. VNS is a way of using the vagus nerve to modulate brain function. VNS is already approved for the treatment of epilepsy and studies have shown promise in treating depression. The FDA announced last year that VNS was approved for the treatment of chronic, treatment resistant depression. VNS is the first treatment to be approved for treatment resistant depression. Studies suggest that VNS may work when medications fail, and that it may help maintain remission in the long-term. However, it is important to keep in mind that acute response rates are low in comparison to ECT, and that this therapy is a long-term implant, designed to aid with long-term management.