American neurologist and psychiatrist Prof Helen Mayberg was in Dublin recently to brief researchers at the Royal College of Surgeons of Ireland on her pioneering work using deep brain stimulation as a treatment for severe depression.

The use of deep brain stimulation to treat motor symptoms in Parkinson’s disease is already widely accepted internationally (though not available in Ireland) but the idea of sending electrical currents into the brain to treat depression raises echoes of the controversial electro-convulsive therapy (ECT).

It was widely used by psychiatrists and is still considered an appropriate treatment by the College of Psychiatry in Ireland.

Mayberg, professor of neurology and psychiatry at Emory University School of Medicine, Atlanta, Georgia, points out that deep brain stimulation is considered a treatment option for only 10 per cent of patients with profound depression who haven't responded to psychotherapy or anti-depressant medication.

Experimental phase
The treatment, which is still in an experimental phase, involves the insertion of thin wire electrodes to a targeted part of the brain. These electrodes are connected to a device implanted in the chest from which a high-frequency electrical stimulation is sent at regular intervals to the brain.

In one report, Emory University’s department of psychiatry and behavioural sciences stated that 90 per cent of the 17 patients in its clinical study were “doing well” a couple of years post-surgery.

“This is not an easy solution and requires a skilled team of brain-imaging specialists, neurologists, neurosurgeons, psychiatrists and psychotherapists. We are learning to be more precise with better results. We have to build teams of therapists to work with these patients who need to be retrained in their lives after this invasive experimental treatment,” says Mayberg.

“What we have found with patients is their psychic pain is gone with the treatment. Once the device is put in place, it’s there for several months and we don’t make adjustments.

“The constant brain stimulation takes away the profound mental suffering which allows the patient to re-train to do things they haven’t done in years.”

Severe depression
About 200 patients in Europe and North America have been treated for severe depression using deep brain stimulation. "We have had 80 per cent sustained response from patients in Atlanta and 63 per cent response in a Toronto study. We have taken the device out for some people.

“What we really need is biomarkers so we don’t implant people who have overlapping symptoms for other diseases. It doesn’t treat anxiety, for instance,” she says. Patients who receive the surgery continue with their previous therapeutic interventions after treatment.

“Progress in medicine is not about holding on to false beliefs from the past. If there is a biological basis for depression, this will reduce the stigma without dismissing the psychosocial aspects.

“Depression is not a weakness of character. We are smarter now about medicine and biology and neuroscience and have learned that we can do better while being ethically mindful at every junction and involving the patient.

“Our job is to help chronically ill people get back to being well. These people are off the grid in society. As our work develops, it can engender hope and optimism for people who are suffering and no longer think there is anything out there for them.”

Mayberg and her researchers have also carried out other pioneering studies using brain-imaging techniques to look at parts of the patients’ brains before and after treatment with cognitive behaviour therapy (CBT) or medication.

“Through brain-imaging, we have found that CBT affects the thinking parts of the brain – the frontal cortex predominantly – while drugs impact on the brain stem and the limbic system and only secondarily on the cortex,” she explains.

Correct treatment
"We acknowledge that people have different roads that lead them to depression – early trauma, family history, a stroke or neurological disease – and that people's brains and their environment interact but the way the brain is when you are depressed may give important information to selecting the correct treatment. We want to develop biomarkers to choose the optimal treatment," she says.

“It’s still early days and our data showing how patients with different brain patterns will respond more effectively to either CBT or drugs is one of the first to be published. We’ve done very badly in the last 40 years [in terms of] choosing the right treatment for depression.

“If these studies are replicable and reliable, brain patterns can be a starting point to discriminate these depression subtypes to then choose the right treatment.”