Psychedelic drug users throughout the ages have described their experiences as mind-expanding. They might be surprised, therefore, to hear that psilocybin – the active ingredient in magic mushrooms – actually decreases blood flow as well as connectivity between important areas of the brain that control perception and cognition.
The same areas can be overactive in people who suffer from depression, making the drug a potential treatment option for the condition.
The study is the first time that psilocybin's effects have been measured with fMRI, and the first experiment involving a hallucinogenic drug and human participants in the UK for decades.
Franz Vollenweider, who works in a similar field at the Psychiatric University Hospital Zurich, Switzerland, says that the immediate effects of psilocybin are not as important for clinical benefit as the longer-term effects. That's because psilocybin increases the expression of genes and signalling proteins associated with nerve growth and connectivity, he says: "We think that the antidepressant effects of psilocybin may be due to a possible increase of factors that activate long-term neuroplasticity."
We tend to associate drug use with the onset of mental health problems - the oft told link between cannibis use and schizophrenia, for example - so it is good to see the other side of the story. Indeed, drugs such as nicotine are also beneficial in providing a small stimulus - how many folk will tell you how a fag and a coffee act to get things going! Perhaps, the prevalence of drug use among people with mental health problems is them searching for remedies or for methods to cope?