Above: Professor Colleen Loo
By Yasmin Noone
Older people living with depression could be treated for their condition via a weak, non-invasive electrical current applied directly to their brain, according to the results of a new Australian study conducted by the University of New South Wales (UNSW) and the Black Dog Institute.
The Australian study – the largest randomised controlled trial of transcranial Direct Current Stimulation (tDCS) ever– showed that stimulating the brain with a weak electrical current is not only a safe and effective form of treatment for depression, but it could offer other potential new and unexpected physical and mental benefits.
According to the research results, recently published in the British Journal of Psychiatry, tDCS offers significant antidepressant effects, is not associated with any adverse outcomes, and improves attention and information processing.
Trial leader from UNSW’s School of Psychiatry and researcher at the Black Dog Institute, Professor Colleen Loo, explained that, after a single session of tDCS, participants in the active treatment group showed greater improvements in information processing compared to those in the placebo group.
“One participant with a long-standing reading problem said his reading had improved after the trial and others commented that they were able to think more clearly,” Prof Loo said.
“Another participant with chronic neck pain reported that the pain had disappeared during the trial. We think that is because tDCS actually changes the brain’s perception of pain.
“…We are really excited by this finding. [Improved cognition] could be a side benefit of tDCS and because the elderly sometimes experience slowness in thinking or memory, it could be particularly helpful to the elderly…
“We believe these cognitive benefits are another positive aspect of the treatment worthy of investigation.”
A non-invasive form of brain stimulation, tDCS passes a weak depolarising electrical current into the front of the brain through electrodes on the scalp. Patients remain awake and alert during the procedure.
The trial saw 64 depressed participants who had not benefited from at least two other depression treatments receive active or sham tDCS for 20 minutes every day for up to six weeks.
Up to half of depressed participants experienced substantial improvements after receiving the treatment.
“Most of the people who went into this trial had tried at least two other antidepressant treatments and got nowhere. So the results are far more significant than they might initially appear — we weren’t dealing with people who were easy to treat.
“Significantly, results after six weeks were better than at three weeks, suggesting the treatment is best applied over an extended period. Participants who improved during the trial were offered follow up weekly ‘booster’ treatments, with about 85 per cent showing no relapse after three months.
“These results demonstrate that multiple tDCS sessions are safe and not associated with any adverse cognitive outcomes over time.”
Prof Loo clarified that tDCS is “nothing like” electroconvulsive therapy (ECT), formerly known as electroshock, in which seizures are electrically induced in anesthetized patients for therapeutic effect.
“The tDCS current strength is two milliAmps (mA) while for ECT it’s 800-900 mA.
“With tDCS, there is also no seizure, anaesthetic and the person stays wide awake the whole time.”
She also commented that the duration of treatment differs – tDCS requires a session lasting around 20 minutes while ECT (using much stronger currents) lasts for about five minutes.
“It also doesn’t cause any impairment but, it could, on top of treating depression, cause other improvements.
“There’s nothing to say that with tDCS, there should be added precautions for the elderly. But, if anything, there’s side benefits.
“It looks really promising although we need to look at it further to see if we can prove its use as a treatment.”
“…My hunch is that, in the future, it will find its place as a treatment among other existing treatments for depression.”
The researchers are also currently conducting other tDCS trails to investigate whether the treatment can be specifically shown to slow down cognitive decline and improve bipolar disorder.