The chemical structure of psilocybin

    Psilocybin ‘reboots’ the brain and reduces symptoms of depression

    13 October 2017

    Patients taking psilocybin to treat depression show reduced symptoms weeks after treatment following a ‘reset’ of their brain activity, according to new research by Imperial College London.

    Psilocybin – the naturally occurring psychoactive compound found in ‘magic’ mushrooms – was used in a trial on a small number of patients with depression in whom conventional treatment had failed.

    The research, which has been published in the journal Scientific Reports, finds that the benefits of the drug last for up to five weeks after treatment, and believe the psychedelic compound may effectively reset the activity of key brain circuits known to play a role in depression.

    The trial subjects had brain scans taken the day before and after they received the drug treatment. The images revealed changes in brain activity that were associated with marked and lasting reductions in depressive symptoms.

    The authors note that while the initial results of the experimental therapy are exciting, they are limited by the small sample size as well as the absence of a control group – such as a placebo group – to directly contrast with the patients.

    Dr Robin Carhart-Harris, Head of Psychedelic Research at Imperial, who led the study, said: ‘We have shown for the first time clear changes in brain activity in depressed people treated with psilocybin after failing to respond to conventional treatments’

    ‘Several of our patients described feeling ‘reset’ after the treatment and often used computer analogies. For example, one said he felt like his brain had been ‘defragged’ like a computer hard drive, and another said he felt ‘rebooted’. Psilocybin may be giving these individuals the temporary ‘kick start’ they need to break out of their depressive states and these imaging results do tentatively support a ‘reset’ analogy. Similar brain effects to these have been seen with electroconvulsive therapy.’

    During the study 20 patients were given two doses of the drug (10 mg and 25 mg), with the second dose a week after the first.

    Nineteen of these underwent initial brain imaging and then a second scan one day after the high dose treatment. Carhart-Harris and team used two main brain imaging methods to measure changes in blood flow and the crosstalk between brain regions, with patients reporting their depressive symptoms through completing clinical questionnaires.

    Immediately following treatment with psilocybin, patients reported a decrease in depressive symptoms, corresponding with anecdotal reports of an ‘after-glow’ effect characterised by improvements in mood and stress relief.

    Functional MRI imaging revealed reduced blood flow in areas of the brain, including the amygdala, a small, almond-shaped region of the brain known to be involved in processing emotional responses, stress and fear. They also found increased stability in another brain network, previously linked to psilocybin’s immediate effects as well as to depression itself.

    These findings provide a new window into what happens in the brains of people after they have ‘come down’ from a psychedelic, where an initial disintegration of brain networks during the drug ‘trip’, is followed by a re-integration afterwards.

    Professor David Nutt, the study’s senior author said: ‘Larger studies are needed to see if this positive effect can be reproduced in more patients. But these initial findings are exciting and provide another treatment avenue to explore.’