Novel treatment shows promise in alleviating suicidal symptoms
Can brain cell activity identify which patients will benefit from a new type of depression treatment?
This was the question driving a new CAMH study of a novel treatment called magnetic seizure therapy (MST) among people seriously ill with depression.
Current depression treatments hadn’t worked for these study participants. In fact, up to 40 per cent of people with depression don’t respond to at least two, and often more, different medications. In such cases, electroconvulsive therapy (ECT) may be prescribed, but it is not widely used due to its side effects on memory as well as stigma associated with it.
“MST is a potential alternative treatment, since it’s shown to be effective in reducing symptoms of depression, and it doesn’t have the memory loss that can occur with ECT,” says Dr. Jeff Daskalakis, Chief of Mood and Anxiety Disorders at CAMH, and senior author on the study, published in April 2016 in JAMA Psychiatry.
Dr. Jeff Daskalakis demonstrates magnetic seizure therapy in CAMH's Temerty Centre for Therapeutic Brain Intervention
The research team sought to identify a biological “marker” in the brain to indicate which participants would have fewer suicidal symptoms following MST. With MST, a smaller part of the brain is stimulated, since magnetic waves are used, instead of an electric current applied directly to the scalp with ECT. Although there are fewer side effects, MST is still an intensive procedure requiring up to 24 sessions and the use of anesthesia.
The study's results, based on 27 people who completed a course of MST, are promising, says Dr. Daskalakis, Co-Director of the Temerty Centre for Therapeutic Brain Intervention and Clinician Scientist in the Campbell Family Mental Health Research Institute.
The biological target – or biomarker – the team measured is called cortical inhibition. It refers to the activity of neurons in the brain that work to “calm” or inhibit the excitatory neurons in the brain.
In the week before treatment, researchers measured suicidal thoughts, using a widely used questionnaire called the Scale for Suicidal Ideation (SSI). Cortical inhibition was measured two ways, using a combination of brain stimulation and electroencephalography (EEG).
Before treatment, participants had an average score of 9 on the suicide scale, with 8 of 27 people reporting a score of 0, meaning no suicidal thoughts. After treatment, the average dropped significantly to a score of 4, with 18 of 27 people having no suicidal thoughts.
People with the strongest levels of cortical inhibition before receiving MST were most likely to have fewer suicidal symptoms after MST. “The results were accurate 9 times out of 10,” says Dr. Daskalakis. “Essentially, the healthier your brain physiology, the more likely you will respond to MST.”
The study, led by first author and PhD student Yinming Sun, suggests that cortical inhibition is a promising approach to identifying who will respond to MST in relation to suicidal thoughts.