Teen marijuana use may have next-generation effects

October 28, 2019

Science Daily/University of Washington

A new study shows how a parent's use of marijuana, past or present, can influence their child's substance use and well-being.

Substance use at any age has consequences. Studies frequently cite the negative impacts -- and occasionally tout some benefits of limited consumption -- of alcohol and marijuana.

What is less known is how patterns of alcohol or marijuana use in one phase of life can affect the next generation, even long after an individual has stopped using.

A new study by the University of Washington's Social Development Research Group shows how a parent's use of marijuana, past or present, can influence their child's substance use and well-being.

"The really important takeaway is that parent history of marijuana use is an important risk factor for kids," said Marina Epstein, lead author of the study and a project director at the SDRG, which is part of the UW School of Social Work.

The study, published online Sept. 9 in the journal Psychology of Addictive Behaviors, builds off previous work that had grouped participants according to whether, when and how often they used, and examined impacts to their health and behavior. That study found four distinct patterns: "nonusers"; "adolescent-limited" (confined to only that period of life); "late onset" (starting in their late teens, early 20s); and "chronic" (ongoing and frequent). This study is based on a subset of the original participants who have become parents, and has linked parents' past use of marijuana to their children's use of and attitudes toward alcohol and marijuana, other problem behavior, and school achievement.

The original investigation involving parents began in the 1980s when the now-adults were in fifth grade at several Seattle elementary schools. Researchers have followed the participants ever since. In 2002, when the participants were 27, SDRG recruited those who had become parents and began interviewing their children about alcohol beginning at age 6, and marijuana starting at age 10. To date, 360 children completed interviews between the ages of 10 and 20.

Children and teens of chronic users were most likely to use alcohol and marijuana themselves, as researchers had predicted. But what came as more of a surprise was the behavior of children whose parents had primarily used during adolescence: Compared to the children of nonusers, children of adults in the "adolescent-limited" group were more than 2.5 times as likely to use marijuana and 1.8 times as likely to use alcohol. This was true even after parents' current marijuana use was accounted for.

In comparison, children of chronic users were nearly 4.5 times as likely to use marijuana, and 2.75 times as likely to use alcohol, as children of nonusers.

Children in the "late-onset" group, as it turned out, were least likely to use marijuana, as were children of nonusers. They did, however, have lower grades.

"Using marijuana in adolescence is associated with a host of other problems in the present and later into adulthood," said Epstein, who was the lead author on the earlier paper that established the marijuana usage patterns. "Now we see that echoing through to their children."

According to that prior study, people who used marijuana during their teen years tended to have poorer functioning during the period in which they were actively using, and, by their early 30s, to have lower academic and economic outcomes than people who started using as adults, or who never used.

Chronic users had the worst outcomes in terms of health and quality of life, Epstein added: Poor mental health, lower academic outcomes, less financial stability and greater tendency of criminal and/or risky behaviors were associated with frequent, lifetime marijuana use.

The researchers need additional studies to uncover reasons for the relatively high usage patterns among children in the adolescent-limited group. There may be a connection between a parent's use during adolescence, for example, and their subsequent attitudes toward substance use among teenagers in general, Epstein said.

Today, 33 states have legalized marijuana in some form, often for medical purposes, and of those, 11 states -- including Washington -- have legalized it for recreational use. Those developments have implications for how parents talk to their children about marijuana and how health care providers talk to patients. Even a routine review of a child's health history could include a question about a parent's history of marijuana use -- just to consider the potential impact on the child, Epstein said.

"Now that marijuana is legal, we have to be able to talk to parents about how they're using, and to be more specific -- how much, how often, whether this is lifelong pattern," said Epstein. "The landscape of marijuana is changing, and we have to be mindful of it."

https://www.sciencedaily.com/releases/2019/10/191028164418.htm

Early use of marijuana can increase its negative health impacts

A study cautions of risks for young consumers

March 28, 2017

Science Daily/Concordia University

With new legislation imminent in Canada, marijuana is a hot topic these days. Those who smoke it may be cheering. Those who've never tried it may be thinking, why not? And those looking to make a business out of it are grappling with how to navigate a challenging product.

But one of the most contentious aspects of legalization is age. A report by the Canadian Task Force on Cannabis Legalization and Regulation, released in December 2016, recommends marijuana use be restricted to those 18 years old and older.

The need for age guidelines falls in line with a new study by James McIntosh, professor of economics in the Faculty of Arts and Science. Recently published in the journal Health, the findings show that young users report the most impact to their physical and mental health.

The article also shows that those who wait until the age of 21 to use the drug are unlikely to develop a lifelong habit.

Heightened risks for youth

For the study, McIntosh and his co-author Rawan Hassunah (BA 16) examined the results of three national surveys on tobacco, alcohol and drug use -- two in Canada and one in the United States.

"We wanted to see what the effects of regular marijuana use were on self-reported physical and mental health," McIntosh explains.

The report cites other studies demonstrating the negative impacts of marijuana. It's the first, however, to look so closely at age of first use.

In terms of overall effects, the study confirmed that marijuana does affect people's physical and mental health, that it will cause cognitive impairment, memory loss, diminished IQ, limited educational success and likelihood for developing mental illness. Physically, early users also suffer higher rates of respiratory diseases and certain cancers.

McIntosh says the younger you start, the worse the impacts.

"We found that if age of first use is below 15, it's always bad for you."

The argument for legalization

So how can these findings translate into informing youth about the risks? Besides legislation, McIntosh recommends educational programs, counselling services and a distribution system that minimizes use by young people.

Despite his warnings about age restrictions, however, he says legalization will bring more good than harm.

"The task force outlines these benefits -- to take marijuana out of criminal hands, to tax it, to make sure that product quality is preserved."

McIntosh adds that being at the cusp of legalization puts Canada in a unique position to begin rigorous study of cannabis and its effects.

"We need to start collecting data on it to see what the effects are on people of all ages. You can get all kinds of information on drinking behaviours -- they should do that with marijuana."

https://www.sciencedaily.com/releases/2017/03/170328105901.htm

Exposure to cannabis and stress in adolescence can lead to anxiety disorders in adulthood

January 8, 2019

Science Daily/Universitat Pompeu Fabra - Barcelona

A new study conducted on laboratory animals shows that exposure to cannabis and stress during adolescence may lead to long-term anxiety disorders characterized by the presence of pathological fear. The work carried out by the Neuropharmacology Laboratory-NeuroPhar at Pompeu Fabra University, was led by the researchers Fernando Berrendero, now at Francisco de Vitoria University, and Rafael Maldonado, and has been published in the journal Neuropharmacology.

Cannabis remains the most commonly consumed illegal drug worldwide. Its regular use often begins during adolescence, which is especially troubling because this period is crucial for the brain to mature properly through the reorganization of the neuronal synapses.

Numerous preclinical and epidemiological data suggest that exposure to cannabinoids in adolescents may increase the risk of the onset of psychiatric illnesses in adulthood. The results of the National Drugs Plan show an increase in the consumption of cannabis and a recent review highlights that in recent years the perception of the risk of its consumption has diminished among the young population, from 12 to 17 years of age, the age group discussed in this article.

"In this study we have investigated the effects of simultaneous exposure to Δ9-tetrahydrocannabinol (THC), which is primarily responsible for the psychoactive properties of cannabis, and to stress during adolescence," explain Rocio Saravia and Marc Ten-Blanco, first authors of the article. Specifically, they have studied how this exposure during adolescence affects the extinction of the memory of fear in adult mice.

Occasionally, a stimulus that should be neutral, as could be, for example, seeing the dentist in a white coat, is associated with a threatening one, which would be the pain we have felt upon previous visits to the dentist, and causes a fear response. Normally, fear reactions diminish over time as the conditioned stimulus ceases to be associated with the negative experience. This is known as fear extinction. But when fear extinction does not occur properly, anxiety disorders such as post-traumatic stress syndrome, phobias or panic attacks occur.

"We have observed that adolescent mice treated with THC and exposed to stress display impaired fear extinction in adulthood. However, this effect was not observed in animals exposed to these same two factors separately," Fernando Berrendero explains. In addition, the resistance to fear extinction was associated with a decrease in neuronal activity in the basolateral amygdala and the infralimbic prefrontal cortex, suggesting a deregulation in the long term of the circuit that regulates fear.

"Our findings highlight the influence of environmental factors such as stress on the harmful effects of the exposure to cannabis during early ages and suggest that the consequences of early cannabis use greatly depend on the environment of its use," explains Rafael Maldonado, full professor of Pharmacology at UPF. "The presence of stress situations, common among consumers of the substance, may worsen the harmful effects of cannabis," he concludes.

Their study has also involved the researchers Humberto Gagliano, Antonio Armario and Raül Andero, of the Autonomous University of Barcelona. The article is part of a project funded by the Spanish National Drugs Plan.

https://www.sciencedaily.com/releases/2019/01/190108125419.htm

Booze and pot use in teens lessens life success

Teens who drank or smoked marijuana heavily are less likely to marry, go to college, or work full time

November 5, 2017

Science Daily/University of Connecticut

Young adults dependent on marijuana and alcohol are less likely to achieve adult life goals, according to new research by UConn Health scientists presented November 5 at the American Public Health Association 2017 Annual Meeting & Expo.

UConn Health researchers examined data from the Collaborative Study on the Genetics of Alcoholism (COGA) to track the effect teenage alcohol and marijuana use has on the achievement of life goals, defined as educational achievement, full time employment, marriage and social economic potential. The study includes 1,165 young adults from across the United States whose habits were first assessed at age 12 and then at two-year intervals until they were between 25 and 34 years old. Most of the study participants had an alcoholic grandparent, parent, aunt or uncle.

Overall, individuals who were dependent on either marijuana or alcohol during their teen years achieved lower levels of education, were less likely to be employed full time, were less likely to get married and had lower social economic potential.

"This study found that chronic marijuana use in adolescence was negatively associated with achieving important developmental milestones in young adulthood. Awareness of marijuana's potentially deleterious effects will be important moving forward, given the current move in the US toward marijuana legalization for medicinal and possibly recreational use," said study author Elizabeth Harari.

The researchers also found that dependence may have a more severe effect on young men. Dependent young men achieved less across all four measures, while dependent women were less likely than non-dependent women to obtain a college degree and had lower social economic potential, but were equally likely to get married or obtain full time employment.

Previous research had shown that heavy use of alcohol or marijuana in adolescence affects people developmentally. This study followed up on that, to look at what happens after age 18. The life outcomes seem to show the differences are meaningful into adulthood.

The study is ongoing.

 "COGA investigators are following many subjects over the years and are using this extensive and growing database to examine several significant research topics," says Dr. Grace Chan, a statistician in the UConn Health department of psychiatry. Chan, Harari and UConn Health Alcohol Research Center Director Victor Hesselbrock are currently looking at whether there are different outcomes between young people dependent on alcohol versus marijuana, as well as why there were marked differences in outcomes between the sexes.

Harari's research was supported by Hesselbrock and Chan. The Collaborative Study on the Genetics of Alcoholism is funded by the National Institute of Alcohol Abuse and Alcoholism.

https://www.sciencedaily.com/releases/2017/11/171105193046.htm