Brain scan study provides new clues as to how electroconvulsive “shock” therapy helps alleviate depression

 

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Pre-treatment, functional connectivity (FC) between fusiform face area and amygdala was reduced in depressed patients compared with healthy controls (HC), but increased after electroconvulsive therapy (from Wang et al 2017)

By Christian Jarrett

In the UK, thousands of people with depression continue to undergo electroconvulsive “shock” therapy (ECT) each year, usually if their symptoms have not improved following talking therapy or anti-depressants, and especially if they are considered to be at high risk of suicide, and the numbers may be rising. The technique, which involves using an electric shock to induce a seizure, carries risks, such as memory problems, but the majority of patients experience symptom improvements, and patient surveys show they generally view it positively. However, some experts remain opposed to its use and question its evidence base.

Despite the continued use of ECT, and its apparent benefits, exactly how it works remains largely unexplained. However, new clues come from a Chinese study, published in Social Cognitive and Affective Neuroscience, in which patients showed increased grey matter volume in the amygdala, a brain structure involved in emotional processing.

Jiaojian Wang at the University of Electronic Science and Technology of China, and her colleagues, recruited 23 patients (average age 39; 12 women) with major depression who had not responded to other treatments and/or were acutely suicidal, and who were due to receive a course of ECT.

The researchers scanned the patients’ brains using fMRI 12-24 hours before their first ECT session and then again 24-72 hours after their last session (the patients averaged seven sessions over a 2-3 week period). The scan was used to assess basic brain structure and to look for connectivity patterns between brain areas while the patients rested. For comparison, the researchers also scanned the brains of 25 healthy controls of similar age and educational background.

After treatment, the patients with depression showed not only improved symptoms but also increased grey matter volume in the left amygdala, specifically in a subregion known as the superficial nuclei. The amygdala is involved in emotional processing; the superficial nuclei is involved specifically in interpreting facial expressions.

Post-treatment, the patients also showed increased connectivity between the fusiform face area (FFA) in the temporal lobe, so-called because of its role in processing faces, and the amygdala. Statistical analysis suggested this was because of an increased effect of the FFA on the amygdala, but this remains somewhat speculative.

At pre-treatment, the patients had reduced grey matter in the amygdala and reduced amygdala–FFA connectivity as compared with the healthy controls, and the more extreme these structural and connectivity features, the more severe the patients’ depression symptoms. This suggests the ECT had acted on aspects of brain structure and function relevant to depression.

Wang and her colleagues speculated that the brain changes they observed in the depressed patients may indicate that ECT “alleviates the symptoms of depression by improving … social abilities to enhance the gaze fixation of face stimuli”. More generally the findings are consistent with previous suggestions that ECT helps promote neuronal growth.

This was a small study and the patients were taking different anti-depressants throughout, so larger, more tightly controlled research is needed to confirm and build on the results.

Electroconvulsive therapy selectively enhanced feedforward connectivity from fusiform face area to amygdala in major depressive disorder

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest and author of Great Myths of the Brain

5 thoughts on “Brain scan study provides new clues as to how electroconvulsive “shock” therapy helps alleviate depression”

  1. As a psychiatric nurse for some 30+ years and a close relative of a patient who received ECT under the Mental Health Act (very much against their will), the issues surrounding ECT are particularly pertinent.

    I have basic concerns about this study in that although there was a ‘healthy control group’, the opportunity was not taken to include a group of depressed patients who received drug treatments alone and no distinction was made between the routes of action or side effects of the anti- depressants taken simultaneously with ECT.

    Some thoughts based entirely on m own experiences:

    Depression, schizophrenia, mania have some shared features related to ‘retreating from a threatening reality’ into a reconstructed world where threats are diminished. This happens either by changing attitudes, thoughts or behaviour towards those threats, as happens in ‘talking therapies’; by dealing with the threat ‘head- on’ e.g. changing the threatening reality in some practical manner e.g. by removal to a place of safety or ending a dysfunctional and/or abusive relationship; or by avoiding the threat or putting off dealing with it (at least temporarily by virtue, of ‘being ill’) , thus taking ‘time-out’ of that reality.

    Some patients expressed relief when diagnosed with depression because they felt that their difficulties with their life had been acknowledged and validated and they ‘had permission’ to be ill. Some took their depression as a signal that something in their lives was fundamentally wrong and took the ‘time- our-opportunity’ to address aspects of their lives that were clearly not conducive to their personal wellbeing and happiness and actively (with support) changed those disruptive aspects. This was not always possible, and where this was the case, then cognitive behavioural therapies that changed attitudes towards that perceived adversity were more effective (ACT).

    I would be very interested to know about the placebo effect, i.e. whether the patients believed the ECT was going to be effective prior to treatment and if there correlational relationships fluctuated with differing doses and duration of ECT. I would also wish to have a comparison between patients who reportedly gain NO benefit from ECT (completely excluded from the data in this study).

    Assumptions made in this study from which bias may result:

    1. Increased connectivity and increased grey matter are directly attributable to the ECT rather than to other variables.
    2. Improved mood was correlated (linear relationship) directly with the ECT treatment, increased connectivity and increased grey matter in the Amygdala. It may be, that improved mood would have occurred regardless of any intervention as a result of normal progression through the illness.
    3. The direction of the correlational relationship is not determined. i.e. did the ECT cause the improvement in depressive symptoms or, was the improvement in symptoms merely coincidental i.e. the ECT had in reality, no effect whatsoever.
    4. Side effects of being coerced into ECT treatment on the basis ‘that although we don’t understand how it works yet, it is always beneficial as a last resort in persistant depression’, do not outweigh any benefit derived.

    I can tell you that the process of being coerced into ECT treatment when resistance to persuasion are lowest), remains a painful experience decades later akin to PTSD.

    For some people, their ‘depression label’ and the support, empathy and person- centred attention their condition elicits becomes a positive, normal aspect of their daily lives. Living the life of a ‘depressed person’ becomes habitual and reinforcing of continued depressive symptoms – a way of life. It becomes more and more difficult to lead a non- depressed lifestyle. I can see you all typing in indignation at this comment! But, anyone who has experienced life in a psychiatric hospital will recognise the ‘revolving door patient’ who is seemingly never ‘happier’ than when ‘depressed’ !

    That is not to denigrate or trivialise the misery experienced by persistant sufferers who go onto take their own lives despite all our best efforts, which is why research must continue. Nevertheless, it is also important to take a more multi- perspective, multi- disciplinary and holistic approach to this biopsychosocial affliction.

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