Electroconvulsive therapy for depression

Depression: Electroconvulsive therapy reduces hyperconnectivity in the brain

21/03/2012

Scottish researchers have studied the use of so-called electroconvulsive therapy (ECT) in depression more closely. "Electroconvulsive Therapy Reduces Frontal Cortical Connectivity in Severe Depressive Disorder," Researchers around Jennifer Perrina and Ian Reida from the University of Aberdeen write in the journal Proceedings of the National Academy of Science (PNAS).

The Scottish researchers believe that, according to the so-called "hyperconnectivity hypothesis" in patients with severe depression, connections within the cortex or between the cortex and the limbic system are increasingly being built up, which have a significant share of the mental illness. Due to the highly controversial electroconvulsive therapy, the cortical connectivity of the subjects and the severity of their depressive symptoms have significantly reduced, the Scottish scientists report.

Reservations about electroconvulsive therapy
The controversial electroconvulsive therapy became known through the film "One Flew Over the Cuckoo's Nest", in which the electric shocks were not used for healing but to punish the patients. Thus, the treatment method developed in Italy and Hungary as early as the 1930s had lost its reputation as an inhuman form of therapy, although to some extent considerable success could be achieved with ECT. Since the treatment of depression based on drugs is possible, the ECT is hardly used. Psychiatrists usually prefer antidepressants, although their effectiveness is often limited. If no success can be achieved with the drugs, ECT remains the last therapeutic option. They are even more widely used in the UK than in the UK: 4,282 ECT treatments were reported in 2010, according to the Scottish ECT Accreditation Network in the United Kingdom.

Effect of electroconvulsive therapy studied
The Scottish researchers cite one of the reasons for the rare use of electroconvulsive therapy, the lack of knowledge about their mode of action. An ECT triggers an epileptic seizure, which, according to Ian Reida, affects the "wiring" of the individual neurons. That's why Aberdeen's brain researchers have used magnetic resonance imaging (MRI) and a "unique data-driven approach to functional connectivity analysis in the brain" to investigate the effects of ECT treatment on nine patients with major depression. Using functional magnetic resonance imaging (fMRI), the scientists were able to draw conclusions about the connectivity of the different brain areas. The observed decline in general connectivity, according to the researchers, was associated with a marked improvement in depressive symptoms.

Reduced connectivity is associated with reduced depressive symptoms
Before and after ECT treatment, depression patients should solve a simple brain-teaser task, with brain activity measured by fMRI. Using a mathematical algorithm, the researchers then calculated the changes in functional connectivity in the subject's brain. They found that in the area of ​​the "left dorsolateral prefrontal cortical region (Brodmann area 44, 45 and 46)" after ECT there was a significant reduction in "average global functional connectivity". This was accompanied by a "significant improvement in depressive symptoms", which was reflected in lower values ​​on the so-called "Montgomery Asberg Depression Rating Scale", write the researchers around Jennifer Perrina and Ian Reida. "Our results show that ECT has a lasting impact on the functional architecture of the brain," says the scientists.

Further research is needed on the use of ECT in depression
According to Ian Reida, the findings support the "hyperconnectivity hypothesis" in depression, where the increased connectivity can not only serve as a "biomarker of mood disorders," but also "a potential therapeutic target." While their study does not provide clear evidence for the link between increased connectivity and the onset of depression, further research is urgently needed, Scottish scientists say. The subjects of the current study should also be further observed to check whether in the onset of depression again hyperconnectivity in the brain of the affected person is recorded. Jennifer Perrina and Ian Reida hope in further investigations also to explore the past weaknesses of the ECT more precisely and possibly even to be able to avoid.

Possible side effects of electroconvulsive therapy
Although ECT already shows a significant effect in 75 to 85 percent of depression patients today, this is often associated with considerable side effects, said the Scottish researchers. For example, after ECT, patients often suffer from memory disturbances, which usually affect the period immediately before and after treatment. Normally, the memory problems go back by themselves after a few hours to days, but the regression may remain incomplete. According to the experts, however, extensive damage to the brain through the use of ECT is not to be feared, and in the future it would also be possible to avoid memory disorders by improving therapy, according to Ian Reida. However, because of the health risks, electroconvulsive therapy is excluded in certain pre-existing conditions such as vascular grafting of the main artery or the vessels of the brain, increased intracranial pressure, or cardiac infarction. In addition, high blood pressure, strokes and coronary heart disease require careful consideration of the benefits of ECT over the risks of failure to treat. (Fp)

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