Teen brain volume changes with small amount of cannabis use, study finds

At a time when several states are moving to legalize recreational use of marijuana, new research shows that concerns about the drug’s impact on teens may be warranted. The study, published in The Journal of Neuroscience, shows that even a small amount of cannabis use by teenagers is linked to differences in their brains.

Senior author and University of Vermont (UVM) Professor of Psychiatry Hugh Garavan, Ph.D., and first author and former UVM postdoctoral fellow Catherine Orr, Ph.D., say this research is the first to find evidence that an increase in gray matter volume in certain parts of the adolescent brain is a likely consequence of low-level marijuana use.

Few studies have looked at the effects of the first few uses of a drug, says Garavan. Most researchers focus on heavy marijuana users later in life and compare them against non-users. These new findings identify an important new area of focus.

Full story at Science Daily

Increased risk of harm from cannabis across Europe

Cannabis resin and herbal cannabis have significantly increased in potency and in price, according to the first study to investigate changes in cannabis across Europe.

The study, published today (Sunday 30 December) in the journal Addiction by researchers from the University of Bath and King’s College London, draws on data collected from across 28 EU Member states, as well as Norway and Turkey by the European Monitoring Centre for Drugs and Drug Addiction.

The findings show that for herbal cannabis, concentrations of delta-9-tetrahydrocannabinol (‘THC’ — the main psychoactive constituent of cannabis) increased by a similar amount each year, from 5% in 2006 to 10% in 2016.

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Cannabis and the brain: Recent studies shed new light

Recent research sheds new light on the effects of cannabis on the brain. It reveals a complex pattern of potential harms and benefits that varies with age and disease.

The findings came from a number of studies that featured at the 2018 annual meeting of the Society for Neuroscience, held in San Diego, CA.

They reveal, for instance, that exposure to marijuana before birth and during teen years can affect the developing brain in several ways.

Full story at Medical News Today

Adolescent cannabis use alters development of planning, self-control brain areas

Adolescent marijuana use may alter how neurons function in brain areas engaged in decision-making, planning and self-control, according to researchers at the University of Illinois at Chicago.

The findings, which were presented at Neuroscience 2018, the annual meeting of the Society for Neuroscience, are the result of an animal model study focused on the structural development of the prefrontal cortex, or PFC, which controls high-level cognitive functions.

Within the PFC, a support structure called the perineuronal net forms a lattice of proteins around inhibitory cells, helping to secure their connections with excitatory neurons and regulate PFC activity. Perineuronal net formation is sensitive to drug use, but the effects of marijuana are not known.

Full story at Science Daily

More than one in ten heavy cannabis users experience withdrawal after quitting cannabis

As the number of Americans who regularly use cannabis has climbed, so too has the number of those experiencing cannabis withdrawal symptoms. A new study by researchers at the Columbia University Mailman School of Public Health and Columbia University Irving Medical Center finds that 12 percent of frequent marijuana smokers experienced Cannabis Withdrawal Syndrome (CWS), which includes emotional, behavioral and physical symptoms. The study is published in the journal Drug and Alcohol Dependence.

CWS was first included in the Diagnostic and Statistical Manual of Mental Disorders in its most recent edition, DSM-5, published in 2013. The new study is the first large-scale report on the link between CWS and DSM-5 psychiatric disorders among frequent U.S. adult cannabis users.

“In a rapidly changing landscape of marijuana laws and attitudes, cannabis use continues to increase among American adults. As a result, more information on the prevalence and correlates of clinical withdrawal in the general population is of critical importance,” said Deborah Hasin, PhD, professor of Epidemiology at Columbia Mailman School of Public Health.

Full story at Science Daily