When psilocybin, the psychoactive compound found in magic mushrooms, was used to treat depression in treatment-resistant patients, it produced rapid and sustained antidepressant effects.
In a paper detailing the study, published today in Scientific Reports, researchers from Imperial College London describe patient-reported benefits lasting up to five weeks after treatment. They believe the psychedelic compound may effectively “reset “the activity of key brain circuits known to play a role in depression.
Comparison of images of patients' brains before and one day after they received the drug treatment 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 to directly contrast with the patients.
According to Dr Robin Carhart-Harris, Head of Psychedelic Research at Imperial, who led the study, "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'.”
In the study, 20 patients with treatment-resistant form of the disorder were given two doses of psilocybin (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 characterized by improvements in mood and stress relief.
Functional MRI imaging revealed reduced blood flow in areas of the brain, including the amygdala. 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.
In August, German scientists reported on a methodology to synthesize psilocybin. And earlier this week another scientific team revealed how psychedelics change molecular signaling in the brain.
Image: Whole-brain cerebral blood flow maps for baseline versus one-day post-treatment, plus the difference map (cluster-corrected, p < 0.05, n = 16). Correlation chart shows post-Treatment changes in bilateral amygdala CBF versus changes in depressive symptoms (r = 0.59, p = 0.01). One patient failed to completed the scan 2 QIDS-SR16 rating, reducing the sample size to n = 15 for the correlation analysis. In all of the images, the left of the brain is shown on the left. Image courtesy of Carhart Harris, R et al. Scientific Reports 2017.