How it can help to give an electric shock

In essence, the reason is that electric shocks appear to have an effect on a specific area in the forward part of the frontal lobe – an area in which, among other things, emotional information relating to an individual’s life is processed.

“Using sophisticated brain scanning methods, we can measure that the positive effect of an electric shock, which is often seen in connection with severe depression, is linked to activation of this area of the frontal lobe,” explains Kamilla Miskowiak, Professor of Psychology at the University of Copenhagen and Psychiatric Centre Copenhagen.

“It’s a well-known fact that this area is active when negative, self-centred thoughts occur in connection with severe depression. Our studies show that electric shocks have the ability to limit this activity and this is completely new knowledge.”

Kamilla Miskowiak headed the study, which has just been published in the international scientific journal European Neuropsychopharmacology. The researchers behind the project are a group of psychologists and psychiatrists from Rigshospitalet, University of Copenhagen, Denmark, and from the University of Oxford, UK, and the study is funded by the Lundbeck Foundation. The study was conducted at Psychiatric Centre Copenhagen and is based on patient trials using electric shock – a treatment method referred to in professional circles as electroconvulsive therapy or ECT.

One of the hallmarks of severe depression is a marked tendency to have negative thoughts. Kamilla Miskowiak explains that, up to now, it has been something of a mystery why electric shocks more or less put a stop to this: “And to find the answers we conducted a trial, which proved to be a major challenge because the patients were in a really bad way.”

In addition to identifying the area of the brain affected by ECT in the case of severe depression, the research team managed to prove something else – something of key importance: “Namely that changes in the neurobiology of the brain can also lead to changes in an individual’s mental processing of emotional stress,” says Kamilla Miskowiak.

Moreover, Kamilla Miskowiak believes that the researchers have now gained a better understanding of the combined effect of electroconvulsive therapy and anti-depressants when treating severe depression:

“It’s a well-known fact that ECT and anti-depressants often work well in combination. Up to now, we’ve not been able to give a more detailed explanation of why this is – but this new knowledge has taught us where and how ECT works in the brain in connection with severe depression. Specifically, we could see that ECT works in the same networks in the brain as anti-depressants, just in other parts of the network. With this knowledge, we’re beginning to gain an understanding of why medication, which has previously been ineffective in a specific treatment programme, suddenly works when the patient receives ECT at the same time.”

Anaesthetic – but without the electric shock

The ECT trial behind the scientific article was conducted between 2009 and 2015 at Rigshospitalet, University of Copenhagen, and at Bispebjerg Hospital. A total of 27 adults took part, all of whom suffered from severe depression and were hospitalised in the psychiatric ward.

Once the patients had agreed to participate, they were taken individually for electroconvulsive therapy – and ECT electrodes were attached to the heads of all of the patients before they were given general anaesthetic, which is standard procedure.

However, this was a randomised trial: 12 patients were not given the electric shock because there was no electricity in the electrodes while the remaining 15 were given the treatment.

Who received what remained a secret – in full compliance with the rules for the trial. And the participants were not informed when they awoke from the anaesthetic.

24 hours later, the brains of the participants were scanned and, while they lay in the MRI scanner, they were shown a range of images.

“Some of the images were pleasant – for example, a romantic situation or a well-laid table full of delicious food. Other images, on the other hand, were unpleasant – for example, images of burnt children. Then there was a category of images described as neutral. And while they looked at the pictures, we looked into their brains using the scanner,” says Kamilla Miskowiak.

But what could Kamilla Miskowiak and her colleagues actually see when they scanned the brains of the subjects in this situation?

In the first place, they discovered something quite new:

That electric shocks affect the particular area in the frontal lobe where we already know there is increased activity when depressed individuals are tormented by negative thoughts about themselves.

More specifically, the researchers could see:

That an electric shock to this area of the frontal lobe reduces the brain activity that accompanies these negative, depressive thoughts.

To a certain extent, this last discovery is ‘indirect’ because the scanner can’t tell us what the patients were actually thinking while they looked at the various image categories.

However, the scans clearly showed:

That the 15 patients who had received electroconvulsive therapy the day before had less measurable activity in the specific area of the frontal lobe when they were shown the unpleasant images compared with the 12 patients who had been chosen by lot to receive placebo ECT.

Kamilla Miskowiak explains that getting severely depressed, hospitalised patients to participate in a randomised trial – which meant that they might not have immediate access to the treatment they so fervently desired – posed a dilemma.

“It made it difficult to recruit participants and that’s why it took six years to complete the programme. But I greatly admire the patients who agreed to participate to help with our research! These are the people we can thank for our new knowledge about the effect of ECT in cases of severe depression.”

All of the patients who took part in the trial were given ECT immediately afterwards. So, the patients who were chosen by lot to be in the placebo group ‘only’ had to wait two days before receiving electroconvulsive therapy.

The Danish-British trial does not address well-known side effects such as the memory and concentration difficulties which can develop after prolonged electroconvulsive therapy.