Sex & Drugs: Can Substance Use Enhance Your Love Life?

Psychologists from Cincinnati and Las Vegas review the evidence for a link between sex and drugs.

Does taking drugs make you a goddamn sexual tyrannosaurus? Niyantha Shekar/Flickr

Those of us on the political left have had a tough time of it in 2016, but one of the few silver linings in this seemingly endless thunderstorm of a year was the increasing liberalization of drug laws in the US. Laws in favor of recreational marijuana use passed in eight of the nine states that put pot on the ballot, and 25% of Americans now live in a state where smoking weed is legal.

Proponents and opponents of drug decriminalization continue to argue over the costs and benefits of drug use, often without recourse to the facts. So let’s look at the scientific evidence for the effects of drug use on something we’re all interested in: our sex lives.

George Richardson of the University of Cincinnati led an international team of scientists to investigate the link between sex and drugs, and to determine whether there may be any evolved benefits of drug use. They recognized that the use of psychoactive substances has been a feature of human behavior since prehistory, either as recreation, as a spiritual aid, or as a form of medicine. Stimulants like coca leaf and coffee continue to be used to alleviate fatigue and enhance alertness; opiates numb pain and produce euphoria; even tobacco, despite its carcinogenic properties, may guard against parasitic infection — an important concern for all humans before the advent of modern medicine and clean drinking water.

So, drugs may have helped humans to survive and thrive. But could they also have helped us find a mate?

It’s true that drug users have a greater number of sexual partners, have sex for the first time at a younger age, and engage more frequently in so-called “risky” sexual behaviors, such as unprotected sex. This could be because certain drugs, such as alcohol, reduce our inhibitions and make us more likely to agree to sex we otherwise would not. Or perhaps drug use and sexual behavior are both linked to some other aspect of psychology. For example, some people are more disposed to live fast and die young (adopting what biologists call “a fast life-history strategy”). These people tend not to worry about the distant future but instead live life in the here and now, chasing after short-term sexual relationships and indulging in transient pleasures — such as drugs — while ignoring the far-off consequences.

Because it is not clear why drug use is connected to sexual behavior, Richardson’s team dug into the data of the National Longitudinal Survey of Youth, which began following American teenagers in 1997. This survey, repeated every two years with the same respondents, features questions about many aspects of life. There are questions about drug use and questions about sexual history.

Richardson’s team was particularly interested in the questions about marijuana, tobacco, and alcohol use, and a question about number of sexual partners in the past year.

The researchers found that the relationship between substance use and sexual experience was not strong, and most of the difference between sexually successful and unsuccessful people was better explained by other variables.

Those who drank a lot of alcohol did report slightly more sexual partners, but the effect was short-lasting. In other words, those who drank a lot had more partners at the same time point, but not in future years. This result is consistent with the idea that alcohol lowers inhibitions and therefore leads to more risky sex. When we sober up, the effect wears off.

An alternative theory — that substance use is associated with more sexual partners because ingesting dangerous and illicit drugs is a way of signalling how strong and hardy you are — was not supported by the data. If drug taking were an advertisement for a resilient constitution, Richardson and colleagues should have seen links between drug use at an early age and sexual success later in life. These links were not evident. So, Charlie Sheen was probably incorrect (surprise surprise) when he boasted about his ability to out-party Keith Richards and Frank Sinatra thanks to the “tiger’s blood” flowing through his veins.

The researchers say:

This study suggests that substance use should likely be understood as reflecting liability to a broad range of “risky” behaviors including multi-partner sex. Our findings imply that … information about [people’s] substance use seems to tell us little about their current prospects for acquiring sexual partners and nothing about their future prospects.

So, if you want to take advantage of the new relaxed laws on drug use, be aware that the effects on your sex life will be as transitory as the high.

Richardson, G. B., Chen, C.-C., Dai, C.-L., Swoboda, C. M., Nedelec, J. L., & Chen, W.-W. (in press). Substance use and mating success. Evolution and Human Behavior. View summary

For an audio version of this story, see the 20 December 2016 episode of The Psychology of Attractiveness Podcast.

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