- A Florey study has shown a single dose of the psychedelic drug psilocybin can improve aspects of social behaviour linked to obsessive-compulsive disorder in male mice.
- The researchers identified changes in brain activity that offer clues to the processes underlying the behavioural effects.
- Their findings build on earlier research showing psilocybin can reduce compulsive grooming in the same mouse model.
A new Florey study points to psilocybin’s potential to address an often-overlooked aspect of obsessive-compulsive disorder (OCD): difficulties with social behaviour.
While OCD is commonly associated with intrusive thoughts and repetitive behaviours, difficulties with social interaction and understanding social information are also recognised features of OCD but remained understudied.
Using a well-established mouse model of OCD, with characteristics of excessive grooming and altered social behaviours, the researchers observed how mice responded to a familiar mouse and a newly introduced unfamiliar mouse.
They found that male mice given psilocybin showed greater interest in an unfamiliar mouse, spending more time interacting with it.
Published in Molecular Psychiatry, the study was led by Florey PhD candidate James Gattuso and graduate researcher Bilgenur Bezcioglu.
“After our previous work showed that psilocybin could reduce compulsive grooming in this mouse model, we wanted to know whether its effects extended to social behaviour,” Mr Gattuso said.
“We found male mice spent less time investigating the unfamiliar mouse than mice without OCD-like features, indicating social dysfunction.
“A single dose of psilocybin restored this social behaviour to levels comparable with those of control mice when assessed seven days later.
“These findings give us a reason to investigate whether psilocybin could help address social difficulties in people with OCD. That is an exciting possibility, but one that needs to be tested in clinical research.”
The team also measured a molecule called c-Fos, a marker of recent brain cell activity, after the social interaction test. Mice that had received psilocybin showed higher levels of this marker in the prefrontal cortex and hippocampus, regions involved in learning, memory and social behaviour.
Professor Anthony Hannan, who jointly supervised the study with Dr Thibault Renoir, said that higher levels of the marker in the infralimbic cortex, part of the prefrontal cortex, were associated with more investigation of the unfamiliar mouse.
“We have identified a link between activity in a specific brain region and improved social behaviour. The next step is to test whether that activity helps produce the improvement,” Professor Hannan said.
“Understanding how psilocybin influences these brain processes could help guide the development of treatments for social difficulties in OCD and related conditions.”
OCD affects an estimated 3 per cent of adults in Australia every year.
