Ecstasy use is a highly heritable behavior, according to study of Dutch twins

Your genetic makeup appears to have a large influence on whether you will ever consume illicit party drugs. New research has found evidence that ecstasy use is a highly heritable trait.

“As a behavioral geneticist I am interested in differences between people in their behaviour, and what causes these differences,” explained Karin J.H. Verweij of Vrije Universiteit Amsterdam, the corresponding author of the study. “Why do some people start smoking or start using drugs whereas others don’t, and why do some people get addicted and others not? I generally approach these questions from a genetics perspective, where I examine whether differences between individuals can be explained by genetic differences between them.”

The study was recently published in the scientific journal Drug and Alcohol Dependence.

Previous research has found that the use of drugs like alcohol, nicotine, cannabis, and cocaine is a heritable behavior. Verweij and her colleagues wanted to know if the same was true of ecstasy, which is also known by its chemical abbreviation MDMA.

“The Netherlands is one of the main producing countries of ecstasy and ecstasy use is relatively common here (especially at dance parties). I wanted to know if genetic influences play a role in why one person does and another does not use ecstasy,” she said.

The study was based on 8,500 Dutch twins and their family members who were between 18 and 45 years old. Scientists have long used twin studies to investigate the relative contributions of genetic and environmental factors.

“We performed a large population based twin study to determine for the first time the heritability of ecstasy use,” Verweij told PsyPost. “With twin studies, individual differences in traits can be partitioned into genetic and environmental influence, by analysing the resemblance in identical twin pairs who share all their genetic material versus non-identical twin pairs who share 50% of their genetic material.”

Only a minority of the sample reported having ever used ecstasy. But the researchers were still able to find preliminary evidence that some people were genetically predisposed to consuming the drug. Heritability was estimated to be around 74%.

“Approximately 10% of our sample have used ecstasy at least once in their life,” Verweij said. “We found that lifetime ecstasy use is highly heritable. This indicates that some people are genetically more vulnerable to start using ecstasy than others.”

But the research has some limitations.

“In our study we looked at lifetime ecstasy use (ever use versus never use); we did not have enough statistical power to also estimate the heritability of other variables of interest, such as frequency of ecstasy use,” Verweij explained. “Another limitation is that we relied on self-report data, which is subject to response-biases such as socially desirable responding.”

“Given that we found that lifetime ecstasy use is highly heritable, in the future studies can try to find genes that play a role in ecstasy use so we can get a better understanding of the biological mechanisms underlying substance use.”

The study, “Heritability of lifetime ecstasy use“, was also co-authored by Jorien L. Treur, Annabel Vreeker, Tibor M. Brunt, Gonneke Willemsen, Dorret I. Boomsma, and Jacqueline M. Vink. It was published online June 15, 2017.