Your brain on psilocybin

‘Psilocybin encourages the growth of neurons into different areas of the brain,’ explains Dr Renee Usdin, who practises integrative medicine. She says that when you take the substance, your body metabolises it into another chemical called psilocin, which binds to serotonin receptors, causing the release of a brain-derived neurotrophic factor (a kind of hormone). This gets the nerve endings growing, increasing connectivity among regions of the brain.

It’s like an orchestra, a Business Insider article explains. Usually, the brain has musical groups that play independently: a sextet here, a quartet there, a jazz trio... Once psilocybin enters, it’s like there’s a conductor: there’s communication between areas that are usually compartmentalised. When new areas in the brain start ‘talking’ to one another, you might experience new insights into old problems.

Psilocybin has also been shown to have an effect on the amygdala, which is involved in processing stress/anxiety and fear. If activity in this region is unbalanced, mood disorders may develop. ‘Psilocybin moderates the amygdala, so those monsters in the basement that you’d usually shut the door on, you can now shine a light on and look at,’ says Leonie. ‘You can confront the monsters rather than be overwhelmed by the fear attached to them.’

NEW PATHWAYS

Several mood disorders and addictive behaviours are linked to what scientists term ‘ruminative thinking’. ‘It’s a way for the brain to efficiently deal with input,’ explains Leonie. ‘But it gets locked into pattern-type thinking. MRIs taken of people on psilocybin show that the default mode network dials down, breaking that pattern of thinking.’

Mendel Kaelen, a researcher at Imperial College, explains: ‘Think of the brain as a hill covered in snow, and thoughts as sleds gliding down the hill. As one sled after another goes down, main trails appear in the snow. Each time a sled goes down, it is drawn into pre-existing trails. In time it becomes more difficult to glide down the hill on any other path or in a different direction. Think of psychedelics as temporarily flattening the snow. The deeply worn trails disappear, and the sled can go in other directions, exploring new landscapes and, literally, creating new pathways.’