Marijuana use episodes linked to partner intimacy experiences

Couple holding hands.

Release Date: May 22, 2019 This content is archived.

Maria Testa.

Maria Testa

“We need to know about the effects of marijuana use, instead of merely assuming what those effects may be.”
Maria Testa, senior research scientist, Department of Psychology
University at Buffalo

BUFFALO, N.Y. – Marijuana use episodes among couples who frequently use the drug increase the likelihood of experiencing intimacy events, according to the results of a University at Buffalo-led study.

“We found robust support for these positive effects within two hours of when couples use marijuana together or in the presence of their partner,” says Maria Testa, senior research scientist in the UB Department of Psychology in the College of Arts and Sciences and the study’s lead author. “The findings were the same for both the male and female partners.”

The study’s definition of intimacy events included love, caring and support.

Testa, a social psychologist who has extensively studied the role of alcohol on partner aggression, says her idea for the current study, funded by the National Institute on Drug Abuse, arose from a lack of information about marijuana’s effects on relationships. She is a member of UB's Clinical and Research Institute on Addictions (CRIA) where she conducted the research.

"I’ve studied alcohol as a predictor of intimate partner aggression for years,” she says. “Because alcohol is related to aggression in general, it’s not surprising to find that aggressive effect in the domain of relationships.

“But survey studies were consistently showing correlations between marijuana use and partner aggression, which didn’t fit with pop culture reports of relaxation and happiness that’s often associated with its use.”

So Testa decided to apply marijuana use to a research context as she had previously done with alcohol use in relationships.

“We need to know about the effects of marijuana use, instead of merely assuming what those effects may be,” says Testa.  “There should also be caution before generalizing these results across a broader population. The conclusions are drawn from within this specific research sample of frequent marijuana-using couples who were mostly white and employed.

“This is science, not advocacy.”

These results should also be viewed in light of a separate paper Testa recently published, using the same sample, that showed increased likelihood of partner conflict within two hours of using marijuana. The conflict effects were modest, however, compared to the robust intimacy effects.

The findings, which appear in the journal Cannabis, can help inform clinicians about how people view their marijuana use within their relationships.

“If you’re a treatment provider it’s going to be difficult to get people to reduce or stop their use entirely because these couples see marijuana as something positive in their relationship,” says Testa. “To ignore that is to make it more difficult for people to change their behavior.”

For the current study, Testa and Kenneth Leonard, director of CRIA; Weijun Wang, a CRIA research scientist; and Jaye Derrick, an assistant professor of social psychology at the University of Houston, recruited 183 married or cohabiting heterosexual couples through social media postings and ads in free distribution newspapers. To be eligible, couples had to be living together more than six months and at least one of them used marijuana a minimum of two time a week, with no intention of quitting or seeking treatment.  The partners were between 18- and 30-years-old and reported no mental illness, current pregnancy or use of cocaine or other stimulants.

Over a 30-day period, each participant reported marijuana use and intimacy events independently using their smartphones.  The researchers used a two-hour window to measure intimacy after use because of previous studies suggesting the effects of marijuana diminish two-to-three hours after use.

“There is very little research on the immediate consequences of marijuana use and intimacy, so this study fills an important gap in the literature,” says Testa. “These results clearly suggest what those consequences are, at least for frequent users.”

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