A single dose of (+/－)-3,4-methylendioxymethamphetamine (MDMA) reopens a critical period in brain development and makes social interactions more rewarding for adult mice, reveals a study published online in Nature this week. The finding might aid the development of treatments for neurodevelopmental disorders and may help to explain why MDMA could sometimes be a useful therapy for post-traumatic stress disorder (PTSD).
Critical periods are ‘windows’ during development when the brain is particularly sensitive to environmental stimuli, such as language or sound. Gul Dolen and colleagues have identified a critical period for social interaction in mice that begins at sexual maturity and ends when the animals become mature adults. The period is underpinned by changes in oxytocin signalling in the nucleus accumbens (the brain’s reward centre), and when it comes to an end, the animals’ appetite for social interaction begins to decline. A single dose of MDMA re-opens this window, causing changes in oxytocin signalling and behavioural changes in mice that last for at least two weeks.
The US Food and Drug Administration (FDA) recently designated MDMA-assisted psychotherapy as a ‘Breakthrough Therapy’ for PTSD. It has been unclear how the therapy, currently in phase III clinical trials, works. This study suggests that the drug may re-open the critical period for social reward learning, helping to deepen the relationship between psychologist and patient.