Psilocybin, a hallucinogenic compound found in magic mushrooms, may help re-set the activity of neural circuits in the brain that are involved in depression.
Magic mushroom enthusiasts have long believed that the drug’s ability to induce profound-feeling experiences could be therapeutically useful. Brain-imaging studies have shown that psilocybin targets areas of the brain overactive in depression.
Last year, Robin Carhart-Harris of Imperial College London and his colleagues conducted the first clinical trial of using psilocybin to treat depression, and got some encouraging results. The trial only involved 12 people and no control group, but the team found that after two sessions of psilocybin-assisted psychotherapy, all of the volunteers had reduced symptoms.
Now Carhart-Harris and his team have shown that psilocybin seems to cause changes in the brains of people with depression. The study involved 19 people who, like in the previous study, had depression that had not been helped by conventional treatments.
Each volunteer was given a 10 mg and 25 mg dose of psilocybin, seven days apart. Brain scans showed that, after taking the drug, activity in some regions of the brain reduced. These areas included the amygdala, which plays a role in processing stress and fear. The participants reported an immediate improvement in mood that lasted for up to five weeks.
“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,” says Carhart-Harris. “Several of our patients described feeling ‘reset’ after the treatment.”
“This is further evidence that psilocybin may turn out to be effective for the most stubborn depression,” says Paul Morrison, of King’s College London. “Developments in this area are a priority in psychiatry. Some people can go through years of suffering, which resist all standard therapies.”
Carhart-Harris’s team warned that people should not attempt to self-medicate with psychedelic drugs.