Study finds less domestic violence among married couples who smoke pot

BUFFALO, N.Y. – New research findings from a study of 634 couples found that the more often they smoked marijuana, the less likely they were to engage in domestic violence.

The study, conducted by researchers in the University at Buffalo School of Public Health and Health Professions and Research Institute on Addictions (RIA), appeared in the online edition of Psychology of Addictive Behaviors in August.  

The study attempted to clarify inconsistent findings about domestic violence among pot-smoking couples that primarily has been based on cross-sectional data (i.e., data from one point in time).  Looking at couples over the first nine years of marriage, the study found:

• More frequent marijuana use by husbands and wives (two-to-three times per month or more often) predicted less frequent intimate partner violence (IPV) perpetration by husbands.
• Husbands’ marijuana use also predicted less frequent IPV perpetration by wives.
• Couples in which both spouses used marijuana frequently reported the least frequent IPV perpetration.
• The relationship between marijuana use and reduced partner violence was most evident among women who did not have histories of prior antisocial behavior.

The study’s lead author is Philip H. Smith, PhD, a recent doctoral graduate of the UB School of Public Health and Health Professions and now associate research scientist in the Department of Psychiatry at Yale University.  

It is based on research data collected by lead investigator Kenneth Leonard, PhD, director of the UB Research Institute on Addictions.  The study was supported by a grant from the National Institute on Alcohol Abuse and Alcoholism to Leonard and a grant to Smith from the National Institute on Drug Abuse.

“These findings suggest that marijuana use is predictive of lower levels of aggression towards one’s partner in the following year.” Leonard says.  “As in other survey studies of marijuana and partner violence, our study examines patterns of marijuana use and the occurrence of violence within a year period. It does not examine whether using marijuana on a given day reduces the likelihood of violence at that time.

“It is possible, for example, that — similar to a drinking partnership — couples who use marijuana together may share similar values and social circles, and it is this similarity that is responsible for reducing the likelihood of conflict.

“Although this study supports the perspective that marijuana does not increase, and may decrease, aggressive conflict,” he says, “we would like to see research replicating these findings, and research examining day-to-day marijuana and alcohol use and the likelihood to IPV on the same day before drawing stronger conclusions.

"While couples who reported marijuana use also reported less marital aggression, previous research with these couples found that couples who smoked marijuana were not less likely to divorce. In addition, the current study does not address the potential impact of parental marijuana use on children in the family and other problems associated with daily marijuana use. The most frequent use reported by couples in this particular study was once a week."

In addition to Smith and Leonard, study co-authors are Gregory Homish, PhD, associate professor, R. Lorraine Collins, PhD, professor, and Gary Giovino, PhD, professor and chair, all of the Department of Community Health and Health Behavior, UB School of Public Health and Health Professions, and Helene R. White, PhD, distinguished professor of sociology in the Center of Alcohol Studies, Rutgers University.