By Audrey Quinn
Posting in Science
When all else fails, electroconvulsive therapy can provide unprecedented relief to people with severe depression. British researchers have for the first time uncovered how the treatment may work, which could lead to the development of safer equally effective therapies in the future.
It's hard for me to think of electroconvulsive therapy (ECT) without drawing up thoughts of barbarism. How could electrically inducing seizures ever be justified as a way of helping someone feel better?
But, research shows that in cases of severe depression, ECT can outperform any other available form of treatment. Kitty Dukakis, the former first lady of Massachusetts, says the therapy has made her feel better than she had in 22 years of suffering from chronic depression.
ECT has a 70-90% percent rate for improving depression, though it's typically used as a last resort given its common side effect of memory loss.
Researchers have long assumed that the treatment causes changes in a person's brain chemistry, but its exact mechanisms have remained unclear.
In measuring the connectivity of 25,000 brain areas, researchers found one – the left dorsolateral prefrontal cortex – that appeared to be “hyperconnected” in patients before treatment.
That means for the patients pre-treatment, neurons in their left dorsolateral prefrontal cortex act more in unison than is typical. Haederle continues:
This bolstered an earlier hypothesis, says research fellow Jennifer Perrin, which suggested that in depressed people, cortical structures involved in thinking are too connected to the limbic system that focuses on emotional processing.
The patients showed a decrease in this hyperconnection following ECT, accompanied by an improvement in their depressive symptoms. The researchers' report concludes:
The findings reported here add weight to the emerging “hyperconnectivity hypothesis” of depression and support the proposal that increased connectivity may constitute both a biomarker for mood disorder and a potential therapeutic target.
This new understanding of possible biomarkers of depression could allow for earlier treatment, pre-empting severe depression. It also provides a target for yet-to-be-developed depression treatments that act through less disruptive means than ECT.
[via Pacific Standard]
(Image: fMRI scan highlighting the left dorsolateral prefrontal cortex via Proceedings of the National Academy of Sciences of the United States of America)
May 18, 2012