The drug MDMA makes people more cooperative toward those they trust, according to new research. The finding offers new insights into how MDMA could aid the treatment of post-traumatic stress disorder.
Commonly known as ecstasy or Molly, MDMA is a synthetic compound that alters perception and mood by changing brain chemistry.
The recent study by King's College London in the United Kingdom also identifies alterations in brain activity that accompany MDMA's impact on cooperative behavior.
The changes occur in regions of the brain that scientists have linked to social interaction and processing.
The researchers, including senior study author Mitul Mehta, a professor in the Institute of Psychiatry, Psychology, and Neuroscience at King's College London, detail their work in a paper that features in the Journal of Neuroscience.
Phase 3 clinical trials are presently testing MDMA as a treatment to accompany psychotherapy for post-traumatic stress disorder (PTSD).
The King's College London study is the first detailed investigation into how MDMA alters cooperative behavior.
"Given the social nature of psychotherapy," says Prof. Mehta, "understanding how MDMA affects social interaction sheds light on why the drug could become a valuable tool in treating patients."
MDMA alters brain chemistry
Current medications do not work in a number of psychiatric conditions that feature difficulty with processing social information.
In this context, regulators in the United States have given MDMA "breakthrough therapy status," effectively putting it on a faster than normal track for development and review.
MDMA alters brain chemistry by increasing the activity of several messenger molecules, including serotonin.
The increased empathy and intimacy that people feel when under the influence of MDMA likely comes from the release of large quantities of serotonin.
Impact on social processing unclear
However, the complexities of how MDMA affects social behavior and processing of social information is not well understood.
To investigate this further, Prof. Mehta and his team recruited 20 adult men in good health and with no history of psychiatric or other neurological illness to take part in their research.
The men took either a typical recreational dose of MDMA or a placebo and then completed a number of tasks.
While they undertook the tasks, a magnetic resonance imaging (MRI) scanner recorded "functional images" of their brains.
One of the tasks that they had to complete was a game of cooperation and trust known as the Prisoner's Dilemma. This game formed the heart of the study.
A game of dilemmas
The game has two players pitched against each other and awards points, depending on which of two decisions each player makes. A player does not know the decision their opponent has made until after both have made their play.
The version of the Prisoner's Dilemma that the participants played involved several rounds. At each round, the players decided whether to cooperate or compete.
If both players chose to cooperate, both won 90 points. If both chose to compete, both won 60 points. When one chose to cooperate and the other chose to compete, the first won only 30 points while the second won 120.
Thus, cooperation is clearly a strategy that avoids low scores, as long as your opponent also cooperates. But do you trust them? Each game has 15 rounds, so there is an opportunity to learn whether to trust or not and decide which strategy to adopt.
The men taking part in the study believed that they were playing against real people. However, their opponents were three different computer programs with pre-set response patterns that differed by the amount of cooperation as the game progressed.
After each round in a game, the players scored their level of trust in their opponent.
MDMA may not affect gullibility
The results showed that cooperation increased as games progressed for those players who took MDMA. However, this only happened when they rated their opponent as trustworthy.
Prof. Mehta says that the researchers were surprised that MDMA did not change the men's opinions of their opponents' trustworthiness.
"Untrustworthy players were rated as low on the scale, whether on MDMA or placebo, and trustworthy players were given equally high ratings," he adds.
The result is significant because it suggests that while MDMA may increase trust, it does not make people more gullible.
From the MRI scans, the team could see that MDMA altered brain activity while the individuals processed the behavior of their opponents, without affecting their decision making.
The scans showed that MDMA increased activity in brain regions linked to understanding the thoughts, intentions, and beliefs of others.
There were also other parts of the brain where the effect of MDMA was different, depending on whether an opponent was trustworthy or not. One of these areas helps to integrate evaluation, uncertainty, and risk.
"Understanding the brain activity underlying social behaviour could help identify what goes wrong in psychiatric conditions."
Prof. Mitul A. Mehta