Electroconvulsive therapy (ECT) is a treatment reserved for the most severe cases of depression, bipolar disorder and schizophrenia. Positive results are not guaranteed.
Could genetic insight in the form of a patient’s “polygenic risk score” help predict whether electroconvulsive therapy will be effective for that patient? This is the focus of a recent study published in American Journal of Psychiatryco-head of Dr. Kaarina Kowalec, assistant professor of pharmacy in the Rady Faculty of Health Sciences at UM. A polygenic risk score is derived from testing a patient’s DNA. It reflects the patient’s “polygenic liability” for certain disorders, based on the presence of genetic biomarkers. “There are differences in our genetics that can increase the risk of disorders like depression and bipolar disorder,” says Kowalec. “Scientists are beginning to demonstrate that genetic biomarkers can also tell us whether someone is more likely to respond to a particular treatment. We can potentially use this information to improve patient outcomes.” The goal of improving patient outcomes was central to Kowalec’s research. When her mother was diagnosed with multiple sclerosis (MS), she wanted to understand why some people with neurological or psychiatric disorders are more likely to have a poor outcome. “I began to realize how much was unknown about these disorders,” she says. “For the past five years, I have researched serious conditions such as schizophrenia and multiple sclerosis that have not responded to treatment.” In films such as One Flew Over the Cuckoo’s Nest, electroconvulsive therapy has been portrayed negatively as a treatment for psychiatric disorders. But it can be extremely helpful for people who don’t respond to other forms of treatment, Kowalec says. The electric current, given to the patient after anesthesia, causes a brief seizure and this can cause changes in brain chemicals. Patients usually take the treatment 8 to 10 times before they start to see improvement. The remission rate after treatment is quite low, between 30% and 50%. Although it is a safe procedure, it can have negative side effects such as memory loss. “Patients may not want to risk the side effects if their genetics suggest they won’t respond,” says Kowalec. “With the multigene risk score, patients could make better informed decisions with fewer risks.” Kowalec, who holds a Ph.D. in genomics and epidemiology, completed a postdoctoral fellowship in Sweden before joining UM in 2019. He co-led the newly published study with Dr. Robert Sigström and Dr. Mikael Landén from Sweden’s University of Gothenburg. Researchers analyzed more than 2,300 patients in Sweden who underwent electroconvulsive therapy for an episode of major depression and agreed to undergo DNA testing through a blood sample. The results revealed that a higher polygenic risk score for major depressive disorder was significantly associated with a lower likelihood of improvement after treatment. “This means that a person who is genetically more prone to major depression is less likely to respond well to ECT,” says Kowalec. On the other hand, being genetically predisposed to bipolar disorder was associated with greater improvement after ECT. The study found no association between polygenic liability for schizophrenia and treatment efficacy for a major depressive episode. The researchers hope to expand the project to study patient responses to ECT worldwide. They would also like to examine the relationship between polygenic risk scores and other forms of psychiatric treatment.
“Based on certain genetic markers, healthcare professionals could categorize patients into those who are more likely and less likely to respond to a particular treatment,” says Kowalec. “This could help patients get the treatment that works best for them much sooner, without trying a series of ineffective treatments.”
Genetic risk for psychiatric disorders associated with brain changes More information: Robert Sigström et al, Association Between Polygenic Risk Scores and Outcome of ECT, American Journal of Psychiatry (2022). DOI: 10.1176/appi.ajp.22010045 Provided by University of Manitoba Reference: Study Shows Link Between Genetics and Response to Electroconvulsive Therapy (2022, October 31) Retrieved October 31, 2022 from
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