Summary: Researchers report MDMA, the main compound in ecstasy, helps people to cooperate better, but only when the other person is trustworthy.
Source: King’s College London.
New research from King’s College London has found that MDMA, the main ingredient in ecstasy, causes people to cooperate better – but only with trustworthy people. In the first study to look in detail at how MDMA impacts cooperative behaviour the researchers also identified changes to activity in brain regions linked to social processing.
Problems with social processing are recognised as a fundamental difficulty in a range of psychiatric conditions and are not treated effectively by current medications. The results of the study, published in The Journal of Neuroscience, may be relevant for psychiatric conditions such as post-traumatic stress disorder (PTSD).
MDMA is used by recreational users due to its profound social and emotional effects and is known to release neurotransmitters – chemical messengers in the brain – linked to behaviour and mood. However, scientists know little about how different neurotransmitter systems in the brain contribute to complex social behaviour.
Twenty healthy adult men were either given a typical recreational dose of MDMA or a placebo pill and completed several tasks while in an MRI scanner, including the Prisoner’s Dilemma. In the Prisoner’s Dilemma players choose to either compete or cooperate with another player. Both players get points if they cooperate, but if one player chooses to compete they receive all the points while the other player gets nothing.
The researchers found participants under the influence of MDMA became more cooperative, but only when interacting with trustworthy players.
Senior author, Professor Mitul Mehta from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN), said: ‘We asked people what they thought of their opponent and, surprisingly, MDMA did not alter how trustworthy they thought the other players were. Untrustworthy players were rated as low on the scale, whether on MDMA or placebo, and trustworthy players were given equally high ratings.’
‘Importantly, MDMA did not cause participants to cooperate with untrustworthy players any more than normal. In other words, MDMA did not make participants naively trusting of others.’
When playing the Prisoner’s Dilemma, participants believed that they were playing real people through a computer. In fact, the ‘people’ were pre-programmed computer responses which behaved in either a trustworthy or untrustworthy manner, differing by how much they cooperated over the course of the game.
First author, Dr Anthony Gabay who carried out the work at King’s College London and is now at Oxford University, said: ‘When trustworthy players betrayed the participants the breach in trust had an equally negative impact whether participants were under the influence of MDMA or not. However, MDMA led to a quicker recovery of cooperative behaviour and this tendency to rebuild a relationship led to higher overall levels of cooperation with trustworthy partners.’
‘Using MRI scans, we were also able to see that MDMA had an impact on brain activity when processing the behaviour of others, rather than altering the decision-making process itself.’
MDMA increased activity in the superior temporal cortex and mid-cingulate cortex, areas known to be important in understanding the thoughts, beliefs and intentions of other people. When processing the behaviour of trustworthy players, MDMA increased activity in the right anterior insula but decreased it when processing behaviour of untrustworthy players, reflecting the different behaviour shown to different opponents. The right anterior insula is important for the integration of appraisals, risk and uncertainty.
Professor Mehta said: ‘Understanding the brain activity underlying social behaviour could help identify what goes wrong in psychiatric conditions. Given the social nature of psychotherapy, understanding how MDMA affects social interaction sheds light on why the drug could become a valuable tool in treating patients.’
MDMA is currently undergoing phase 3 clinical trials for treating PTSD when used alongside with psychotherapy and has been given Breakthrough Therapy designation by the FDA.
Funding: The research was funded by the Medical Research Council.
Source: Robin Bisson – King’s College London
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is credited to King’s College London.
Original Research: Abstract for “MDMA increases cooperation and recruitment of social brain areas when playing trustworthy players in an iterated Prisoner’s Dilemma” by Anthony S Gabay, Matthew J Kempton, James Gilleen and Mitul A Mehta in Journal of Neuroscience. Published November 19 2018.
MDMA increases cooperation and recruitment of social brain areas when playing trustworthy players in an iterated Prisoner’s Dilemma
Social decision-making is fundamental for successful functioning, and can be affected in psychiatric illness and by serotoninergic modulation. The Prisoner’s Dilemma (PD) is the archetypal paradigm to model cooperation and trust. However, the effect of serotonergic enhancement is poorly characterised, and its influence on the effect of variations in opponent behaviour unknown. To address this, we conducted a study investigating how the serotonergic enhancer MDMA modulates behaviour and its neural correlates during an iterated PD with both trustworthy and untrustworthy opponents.
We administered 100mg MDMA or placebo to 20 male participants in a double-blind, placebo-controlled, crossover study. While being scanned, participants played repeated rounds with opponents who differed in levels of cooperation. On each round participants chose to compete or cooperate and were asked to rate their trust in the other player.
Cooperation with trustworthy, but not untrustworthy, opponents was enhanced following MDMA but not placebo (respectively: OR=2.01 95% CI 1.42–2.84, p<0.001; OR=1.37 95% CI 0.78--2.30 n.s.). Specifically, MDMA enhanced recovery from, but not the impact of, breaches in cooperation. During trial outcome, MDMA increased activation of four clusters incorporating precentral and supramarginal gyri, superior temporal cortex, central operculum/posterior insula, and supplementary motor area. There was a treatment-by-opponent interaction in right anterior insula and dorsal caudate. Trust ratings did not change across treatment sessions.MDMA increased cooperative behaviour when playing trustworthy opponents. Underlying this was a change in brain activity of regions linked to social cognition. Our findings highlight the context-specific nature of MDMA's effect on social decision-making.Significance statementWe provide a detailed analysis of the effect of MDMA on cooperative behaviour during interpersonal interactions, as well as the neural correlates underlying these effects. We find that following administration of MDMA, participants behave more cooperatively, but only when interacting with trustworthy partners. While breaches of trustworthy behaviour have a similar impact following administration of MDMA compared to placebo, MDMA facilitates a greater recovery from these breaches of trust. Underlying this altered behaviour are changes in brain activity during the viewing of opponents' behaviour in regions whose involvement in social processing is well established. This work provides new insights into the impact of MDMA on social interactions, emphasising the important role of the behaviour of others towards us.