Marijuana detected in homicide victims nearly doubles

Marijuana detected in homicide victims nearly doubles

Researchers at Columbia University Mailman School of Public Health assessed the time trends in alcohol and marijuana detected in homicide victims and found that the prevalence of marijuana almost doubled, increasing from 22 percent in 2004 to 42 percent in 2016. Alternately, the prevalence of alcohol declined slightly from 40 percent in 2004 to 35 percent in 2016. The findings are published in Injury Epidemiology.

"Despite the growing body of evidence linking alcohol and marijuana to homicide victimization, until now there was little information about the contemporary trends in the prevalence of alcohol and marijuana among homicide victims in the United States," said Guohua Li, MD, DrPH, professor of Epidemiology at Columbia Mailman School.

The researchers analyzed toxicological data for homicide victims from the 2004-2016 National Violent Death Reporting System (NVDRS), a population-based surveillance system for violent deaths occurring in the U.S. and administered by the Centers for Disease Control and Prevention. The study sample included homicide victims in 9 states that have been participating in the NVDRS since 2004: Colorado, Georgia, Massachusetts, New Jersey, Oregon, Rhode Island, South Carolina, Virginia, and Wisconsin. The NVDRS recorded a total of 30,433 homicide victims in the 9 states, of which there were 12,638 homicide victims aged 15 years and older with toxicological testing results available for analysis.

Of the 12,638 homicide victims, 37.5 percent tested positive for alcohol, 31 percent were positive for marijuana, and 11 percent were positive for both substances.

The results also showed that male victims were more likely than female victims to test positive for alcohol, marijuana, and both substances. Over two-thirds of adolescent victims aged 15-20 years in 2016 tested positive for marijuana. "We observed marked increases in the prevalence of marijuana in both sexes and across age and racial groups," said Li, who is also a professor of anesthesiology at Columbia University Vagelos College of Physicians and Surgeons.

As of June 2019, 34 states and the District of Columba have legalized marijuana for medical use; of them, 11 states and the District of Columbia have also legalized recreational marijuana for adults aged 21 years and older.

"Our findings are of public health significance because previous research has established marijuana use as an important risk factor for homicide victimization. The impact of increased permissibility and availability of marijuana on violence and injuries needs to be closely monitored and rigorously studied," said Dr. Li.

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Materials provided by Columbia University's Mailman School of Public Health. Note: Content may be edited for style and length.

Teens are using a highly potent form of marijuana

Cannabis sativa plant

Nearly one in four Arizona teens have used a highly potent form of marijuana known as marijuana concentrate, according to a new study by Arizona State University researchers.

Among nearly 50,000 eighth, 10th, and 12th graders from the 2018 Arizona Youth Survey, a biennial survey of Arizona secondary school students, one-third (33%) had tried some form of marijuana, and nearly a quarter (24%) had tried marijuana concentrate.

Marijuana concentrates have about three times more THC, the constituent of marijuana that causes the "high," than a traditional marijuana flower. This is concerning because higher doses of THC have been linked to increased risk of marijuana addiction, cognitive impairment and psychosis, said the study's lead researcher, Madeline Meier, an ASU assistant professor of psychology.

The research team also found that teens who used concentrates had more risk factors for addiction. The researchers compared teens who had used marijuana concentrates with teens who had used some form of marijuana but not marijuana concentrates and teens who had never used any form of marijuana on known risk factors for addiction, such as lower perceived risk of harm of marijuana, peer substance use, parental substance use, academic failure and greater perceived availability of drugs in the community. They found that teens who had used marijuana concentrates were worse off on every addiction risk factor.

"This is important because it shows that teens who have a diverse array of risk factors for developing marijuana addiction may be further amplifying their risk for addiction by using high-THC marijuana concentrates," explained study co-author, Dustin Pardini, an associate professor in ASU's School of Criminology & Criminal Justice.

The study "Cannabis Concentrate Use in Adolescents," is published in the early online edition (Aug. 26, 2019) of Pediatrics.

The team -- which includes ASU researchers Meagan Docherty, School of Criminology & Criminal Justice; Scott Leischow, College of Health Solutions; and Kevin Grimm, Department of Psychology -- also found that teens who had used concentrates had much higher rates of e-cigarette use. One explanation for this might be that teens are using e-cigarettes to vape marijuana concentrate, according to Meier. Earlier studies, including those by Meier, have shown that youth put marijuana in e-cigarettes to conceal their marijuana use.

"Vaping marijuana can be passed off as nicotine vaping," Meier explained.

This finding reinforces the recent decision by the Food and Drug Administration to impose new restrictions on e-cigarettes and their constituents as a means of reducing marijuana use, according to the researchers.

Marijuana concentrates don't look like the traditional marijuana flower. Concentrates can look like wax, oil, or a brittle substance that shatters easily.

"What concerns me most is that parents might have no idea that their child is using marijuana, especially if their child is using marijuana concentrate," said Meier. "Marijuana is not harmless, particularly for adolescents."

Meier's earlier research suggests that frequent marijuana use from adolescence through adulthood is associated with IQ decline. Pardini's prior research has linked regular marijuana use during adolescence with the emergence of persistent subclinical psychotic symptoms.

The researchers' next steps are to ascertain if concentrate users do in fact exhibit higher rates of addiction, cognitive impairment and psychosis.

The Arizona Youth Survey is administered by the Arizona Criminal Justice Commission (ACJC) through funds appropriated by the Arizona Legislature.