Previous research into marijuana use and partner violence has yielded inconsistent findings and has been based on cross-sectional data (data from one point in time). But a new study that followed 634 couples for their first 9 years of marriage finds that the more often they smoked marijuana, the less likely they were to experience domestic violence.

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The new study suggests a link between couples who smoke marijuana and lower rates of domestic violence.

The study is published in the journal Psychology of Addictive Behaviors and was led by researchers at the University at Buffalo (UB) School of Public Health and Health Professions and Research Institute on Addictions.

Lead author Philip H. Smith, a recent UB doctoral graduate and current associate research scientist at Yale University, based his research on data collected by Kenneth Leonard, director of the UB Research Institute on Addictions.

After assessing couples' first 9 years of marriage, the researchers found that husbands and wives who used marijuana frequently - two or three times per month or more - exhibited less frequent intimate partner violence (IPV) instigation by the husbands.

Additionally, couples in which both partners used marijuana frequently reported the least frequent IPV perpetration.

The researchers add that the link between marijuana use and reduced domestic violence was strongest among women who did not have histories of previous antisocial behavior.

Couples who both smoke pot 'may share similar values, reducing conflict'

Leonard says their findings suggest use of marijuana predicts lower levels of violence toward the partner during the following year.

"As in other survey studies of marijuana and partner violence," he adds, "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."

He suggests that couples who both use marijuana "may share similar values and social circles, and it is this similarity that is responsible for reducing the likelihood of conflict."

The authors conclude their study by noting that it suggests an inverse association between marijuana use and domestic violence in newly married couples; however, marijuana use may also be linked to a greater risk of violence among women with a history of IPV perpetration.

Leonard adds:

"Although this study supports the perspective that marijuana does not increase, and may decrease, aggressive conflict, 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."

A grant from the National Institute on Alcohol Abuse and Alcoholism, as well as a grant from the National Institute on Drug Abuse, helped support the study.

Yesterday, Medical News Today reported on a study that revealed a link between states that legalize medical marijuana and fewer deaths from opioid painkillers.

Additionally, MNT wrote a feature in July that analyzed the medical marijuana debate.