Two recent studies may have discovered how electroconvulsive therapy and its close cousin, magnetic seizure therapy, are so effective at alleviating some mental illnesses, especially severe depression – something that has puzzled psychiatrists and neuroscientists for decades.
Yes, electroconvulsive therapy (ECT), or 'shock therapy', which induces a brief seizure in the brain using controlled doses of electricity, is still being used. Despite, these days, being performed in a way that’s very different to the scene in One Flew Over the Cuckoo’s Nest, probably the most (in)famous depiction of ECT, the treatment still carries a stigma.
It may have a bad reputation, but there’s no denying ECT’s effectiveness in treating some mental illnesses, especially severe depression, where around 80% of patients will experience substantial improvement. However, something that’s stumped psychiatrists and neuroscientists is precisely how the treatment alleviates mental illness. Now, two studies by researchers at UC San Diego may have provided an answer.
“A lot of people are surprised to learn that we still use electroconvulsive therapy, but the modern procedure uses highly controlled dosages of electricity and is done under anesthesia,” said Sydney Smith, lead and corresponding author of both studies. “It really doesn’t look like what you see in movies or [on] television.”
In the first study, the researchers used electroencephalography (EEG) to study the brain activity of patients who received ECT for depression. In the second, they looked at a similar form of treatment called magnetic seizure therapy (MST), which induces a seizure using magnets instead of electrodes. What they found was that both therapies produced increased aperiodic activity in the patient’s brains.
“Aperiodic activity is like the brain’s background noise, and for years, scientists treated it that way and didn’t pay much attention to it,” said Smith. “However, we’re now seeing that this activity actually has an important role in the brain, and we think electroconvulsive therapy helps restore this function in people with depression.”
Neurons constantly cycle through periods of excitation and inhibition that correspond to different mental states. Aperiodic activity helps boost inhibitory activity in the brain, effectively slowing it down.
“Something we see regularly in the EEG scans of people who receive electroconvulsive or magnetic seizure therapy is a slowing pattern in the brain’s electrical activity,” Smith said. “This pattern has gone unexplained for many years, but accounting for the inhibitory effects of aperiodic activity helps explain it. It also suggests that these two forms of therapy are causing similar effects in the brain.”
The researchers say their findings suggest that ECT and MST reduce depressive symptoms by restoring healthy levels of inhibition in the brain. While the studies establish a link between aperiodic activity and these treatments, further studies are needed to leverage these insights in clinical applications.
They are currently looking at the possibility of using aperiodic activity as a metric of treatment effectiveness in other depression treatments, including medication.
“At the end of the day, what’s most important to patients and to doctors is that the treatment works, which in the case of ECT, it does,” said Bradley Voytek, a co-author on both studies. “However, it’s our job as scientists to dig into what’s really going on in the brain during these treatments, and continuing to answer those questions will help us find ways to make these treatments even more effective while reducing negative effects.”
Both studies were published in the journal Translational Psychiatry. The first, which looked at the effects of ECT on brain activity, can be found here, and the second, which examined the effects of MST, is here.
Source: UC San Diego