Lazy, maybe, with the munchies and a case of the giggles. But does pot make people violent?

Civil Beat wrote a story in January about a poll by QMark Research, commissioned by the Drug Policy Action Group in partnership with the American Civil Liberties Union.

The poll found more than half of Hawaii voters now want the state to make recreational marijuana legal for adults and there’s growing support for establishing medical pot dispensaries and decriminalizing possession of small amounts.

The Honolulu Police Department said it remains opposed to legalization in part because “research has linked frequent marijuana use with an increase in violent behavior.”

Readers who commented on the story blasted the assertion and called on HPD to share the research supporting the claim.

HPD spokeswoman Michelle Yu told Civil Beat Thursday that the source is the federal Office of National Drug Control Policy’s publication “What Americans Need to Know About Marijuana.”

HPD’s reasoning is a direct quote from the ONDCP publication.

A look at the footnotes shows ONDCP’s sources are two reports: “Adolescent Self-reported Behaviors and Their Association with Marijuana Use” by Janet Greenblatt and “The Risks for Late Adolescence of Early Adolescent Marijuana Use” by Judith Brook. Both studies found increased marijuana use is linked to violent behavior.

But research compiled at, a pro-marijuana site that compiles comprehensive research on marijuana, shoots down studies linking marijuana use to violent behavior.

The site challenges the studies used by the ONDCP. For instance, the website says ONDCP uses a 2001 study by Alfred Friedman in part to claim marijuana is linked to violent behavior.

The study found this to be true, but cautions that the violence may be linked more to drug trafficking or personality than marijuana itself. Friedman even gives a specific note of caution against over-generalizing the findings of a link between marijuana use and violent behavior.

Another study the website says ONDCP uses to back its claim has similar findings. A paper by Evelyn Wei found a link between marijuana use and violence, but says the group of people identified as being more violent the more pot they smoke is “inherently more deviant.”

So is it true, as HPD cited in its reason opposing legalization, that research has linked frequent marijuana use with an increase in violent behavior? Yes.

But does marijuana use increase violent behavior? The research seems inconclusive at best. Most of the studies Civil Beat reviewed that linked the two had major caveats, including personality and drug-trafficking.

There wasn’t much research on whether pot itself causes people to be violent. The papers that did examine this generally found that most people don’t become violent. But some people with aggressive tendencies could become violent if they smoke frequently and tend to become paranoid while high.

Meantime, a federal appeals court ruling Tuesday means marijuana will remain in the “dangerous drug” category, where it’s been for the past 40 years even as states legalize recreational use and doctors prescribe it for a wide range of ailments.

Bottom line: Research has linked marijuana use to violent behavior in some cases, as HPD claims. But generally the studies find that smoking pot in and of itself doesn’t lead to violence. Other factors enter into it, including personality disorders and criminal behavior like drug trafficking. Civil Beat finds this claim to be Half True.

DISCUSSION: What do you think of the research linking marijuana to violent behavior?*

About the Author