Electroconvulsive therapy (ECT) continues to be a highly effective yet controversial tool to treat severe depression in excess of 70 years, and now Scottish researchers the very first time say they’ve discovered why the process often works the actual way it does.

ECT functions by altering how different parts of the brain involved in depression communicate with each other. The University of Aberdeen and University of Dundee researchers, reporting in the journal Proceedings from the Nas (PNAS), said ECT involves anesthetizing patients with serious mood disorders, after which utilizing an electric shock to induce a seizure. They said the technique continues to be the very best treatment available for seven decades.

ECT has the strongest supporting data among treating patients whose depression doesn´t react to medication, according to the American Psychiatric Association. Between 10 and 20 percent of depressed patients received shock therapy, Paul Holtzheimer, an affiliate professor of psychiatry and surgery at Dartmouth School of medicine, who was not active in the new study, told Bloomberg‘s Elizabeth Lopatto.

“This gives us an infinitely more powerful view of the brain,” he told Lopatto inside a telephone interview. “If this study stands up, it informs us this can be a network problem.”

In the Scottish study, nine patients scheduled for ECT had their brains scanned using functional MRI both pre and post treatment. The MRI detects blood flow to specific regions of the mind. The team analyzed the brain´s connectivity utilizing a new mathematical model.

“ECT is a controversial treatment, and one prominent criticism has been that it’s not understood how it works and just what it does to the brain,” said study leader Professor Ian Reid. “However we believe we´ve solved a 70-year-old therapeutic riddle because our study reveals that ECT affects the way in which various areas of the mind involved in depression interact with one another.”

Despite all of the controversy all around the use of shock therapy, the procedure has probably helped 75 to 85 percent of patients get over their symptoms, said Reid.

Reid said all nine patients within the study were identified as having severe depression and were successfully given ECT two sessions each week, typically 8 total treatments. None of the patients in the study had taken care of immediately chemical antidepressants.

Using the new mathematical model to investigate brain connectivity, “i was capable of finding to what extent a lot more than 25,000 different brain areas ℠communicated´ with each other and how the brain´s internal communication patterns differed pre and post ECT treatment in severely depressed patients,” said study co-author Professor Christian Schwarzbauer.

The researchers said their findings advise a “hyper-connection” between your areas of the mind involved in emotional processing and mood change and the parts of the brain involved with thinking and concentrating. Our key finding is that if you compare the connections in the brain pre and post ECT, ECT cuts down on the connection strength between these same areas it reduces this hyperconnectivity.

And so, for the first time we can point to something that ECT does in the brain that makes sense in the context of our opinion is wrong in people who are depressed.

“So far as we know no-one has extended that ℠connectivity´ idea about depression into an arena where you can show cure clearly treating depression, changing brain connectivity,” said Reid. “And also the change that we see in the brain connections after ECT reflects the modification that people see in the symptom profile of patients who generally see a big improvement.”

The team said they now hope to continue monitoring the patients to see if the depression and hyperconnectivity return.

“When we understand more about how ECT works, we will be inside a better position to replace it with something less invasive and more acceptable,” said Reid. “At the moment only about 40 percent of people with depression get better with treatment using their GP.”

The findings can lead to new drug targets which match the effectiveness of ECR without an effect on memory, the researchers noted.

“These findings create a lot of sense,” Professor David Nutt, of Imperial College London, told BBC News. “Indeed, the disabling of connections between different regions of the mind is exactly what I would have predicted from the depression literature.”

“This is why my research group is progressing psilocybin which also disrupts this network, as we showed in PNAS recently as a treatment for depression,” said Nutt, who had been not involved in the Scottish study.

Schwarzbauer said their new method might be “applied to a wide range of other brain disorders such as schizophrenia, autism, or dementia, and may result in a better understanding of the actual disease mechanisms and the growth and development of new diagnostic tools.”

He said more studies can lead to therapies that don´t possess the negative effects of ECT. Confusion, memory loss and physical pain such as muscle spasms are some of the most common negative effects of shock therapy. Also, a better understanding of how the brain region is affected in depression may enable doctors to better target patients who will take advantage of treatment, he added.

“This is the start of an extended process,” Schwarzbauer said. “This is a very novel finding.”