PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Brain changes are associated with casual marijuana use in young adults

Preliminary study suggests effects of drug even in those who are not addicted

2014-04-16
(Press-News.org) Washington, DC — The size and shape of two brain regions involved in emotion and motivation may differ in young adults who smoke marijuana at least once a week, according to a study published April 16 in The Journal of Neuroscience. The findings suggest that recreational marijuana use may lead to previously unidentified brain changes, and highlight the importance of research aimed at understanding the long-term effects of low to moderate marijuana use on the brain.

Marijuana is the most commonly used illicit drug in the United States, with an estimated 18.9 million people reporting recent use, according to the most current analysis of the National Survey on Drug Use and Mental Health. Marijuana use is often associated with motivation, attention, learning, and memory impairments. Previous studies exposing animals to tetrahydrocannabinol (THC) — the main psychoactive component of marijuana — show that repeated exposure to the drug causes structural changes in brain regions involved with these functions. However, less is known about how low to moderate marijuana use affects brain structure in people, particularly in teens and young adults.

In the current study, Jodi Gilman, PhD, Anne Blood, PhD, and Hans Breiter, MD, of Northwestern University and Massachusetts General Hospital/Harvard Medical School used magnetic resonance imaging (MRI) to compare the brains of 18- to 25-year olds who reported smoking marijuana at least once per week with those with little to no history of marijuana use. Although psychiatric evaluations ruled out the possibility that the marijuana users were dependent on the drug, imaging data revealed they had significant brain differences. The nucleus accumbens — a brain region known to be involved in reward processing — was larger and altered in its shape and structure in the marijuana users compared to non-users.

"This study suggests that even light to moderate recreational marijuana use can cause changes in brain anatomy," said Carl Lupica, PhD, who studies drug addiction at the National Institute on Drug Abuse, and was not involved with this study. "These observations are particularly interesting because previous studies have focused primarily on the brains of heavy marijuana smokers, and have largely ignored the brains of casual users."

The team of scientists compared the size, shape, and density of the nucleus accumbens and the amygdala — a brain region that plays a central role in emotion — in 20 marijuana users and 20 non-users. Each marijuana user was asked to estimate their drug consumption over a three-month period, including the number of days they smoked and the amount of the drug consumed each day. The scientists found that the more the marijuana users reported consuming, the greater the abnormalities in the nucleus accumbens and amygdala. The shape and density of both of these regions also differed between marijuana users and non-users.

"This study raises a strong challenge to the idea that casual marijuana use isn't associated with bad consequences," Breiter said.

INFORMATION: This research was funded by the National Institute on Drug Abuse, the Office of National Drug Control Policy, Counterdrug Technology Assessment Center, and the National Institute of Neurological Disorders and Stroke.

The Journal of Neuroscience is published by the Society for Neuroscience, an organization of nearly 40,000 basic scientists and clinicians who study the brain and nervous system. Gilman can be reached at jgilman1@partners.org, Blood at ablood@nmr.mgh.harvard.edu, and Breiter at h-breiter@northwestern.edu. More information on marijuana and addiction can be found on BrainFacts.org.


ELSE PRESS RELEASES FROM THIS DATE:

Study finds new links between number of duplicated genes and adaptation

2014-04-16
Liken it to a case of where two genes are better than one. Scientists have found a class of genes, called small-scale duplication genes, or SSDs, that are important for adapting to novel environments and surviving environmental changes. Published in the advanced online edition of Molecular Biology and Evolution, authors Takashi Makino, Masakado Kawata, et al., were the first to examine more than 30 fully sequenced vertebrate genomes to look at SSDs as genetic signposts that correlated with habitat variability. SSDs have been generated continually during evolution, and ...

New tool advances investigations of disease outbreaks

2014-04-16
To combat disease outbreaks, public health officials often use painstaking fieldwork to try to stay one step ahead of the infectious bugs, linking patients' symptoms to a source of infection to quickly identify the common culprit in related cases. Now, a new field called genomic epidemiology is taking advantage of the rapidly reduced costs of next-generation DNA sequencing to better inform public health officials faced with ongoing outbreaks. In the advanced online edition of Molecular Biology and Evolution, authors Didelot et al. developed a versatile computational ...

Brain anatomy differences between deaf, hearing depend on first language learned

2014-04-16
WASHINGTON – In the first known study of its kind, researchers have shown that the language we learn as children affects brain structure, as does hearing status. The findings are reported in the Journal of Neuroscience. While research has shown that people who are deaf and hearing differ in brain anatomy, these studies have been limited to studies of individuals who are deaf and use American Sign Language (ASL) from birth. But 95 percent of the deaf population in America is born to hearing parents and use English or another spoken language as their first language, usually ...

Chrono, the last piece of the circadian clock puzzle?

2014-04-16
All organisms, from mammals to fungi, have daily cycles controlled by a tightly regulated internal clock, called the circadian clock. The whole-body circadian clock, influenced by the exposure to light, dictates the wake-sleep cycle. At the cellular level, the clock is controlled by a complex network of genes and proteins that switch each other on and off based on cues from their environment. Most genes involved in the regulation of the circadian clock have been characterized, but Akihiro Goriki, Toru Takumi and their colleagues from RIKEN and Hiroshima University in ...

Casual marijuana use linked to brain abnormalities in students

2014-04-16
CHICAGO --- Young adults who used marijuana only recreationally showed significant abnormalities in two key brain regions that are important in emotion and motivation, scientists report. The study was a collaboration between Northwestern Medicine® and Massachusetts General Hospital/Harvard Medical School. This is the first study to show casual use of marijuana is related to major brain changes. It showed the degree of brain abnormalities in these regions is directly related to the number of joints a person smoked per week. The more joints a person smoked, the more abnormal ...

Mothers with higher BMI have increased risk of stillbirth, infant death

2014-04-15
Higher maternal body mass index (BMI) before or in early pregnancy is associated with an increased risk of fetal death, stillbirth, and infant death, with women who are severely obese having the greatest risk of these outcomes from their pregnancy, according to a study in the April 16 issue of JAMA. Worldwide, approximately 2.7 million stillbirths occurred in 2008. In addition, an estimated 3.6 million neonatal deaths (death following live birth of an infant but before age 28 days) occur each year. Several studies have suggested that greater maternal body mass index ...

Thyroid disease risk varies among blacks, Asians, and whites

2014-04-15
An analysis that included active military personnel finds that the rate of the thyroid disorder Graves disease is more common among blacks and Asian/Pacific Islanders compared with whites, according to a study in the April 16 issue of JAMA. Donald S. A. McLeod, F.R.A.C.P., M.P.H., of the QIMR Berghofer Medical Research Institute, Queensland, Australia and colleagues studied all U.S. active duty military, ages 20 to 54 years, from January 1997 to December 2011 to determine the rate of Graves disease and Hashimoto thyroiditis (a progressive autoimmune disease of the thyroid ...

Pre-diabetes and diabetes nearly double over the past 2 decades

2014-04-15
Cases of diabetes and pre-diabetes in the United States have nearly doubled since 1988, suggests new research from the Johns Hopkins Bloomberg School of Public Health, with obesity apparently to blame for the surge. The researchers also found that the burden of the disease has not hit all groups equally, with alarming increases in diabetes in blacks, Hispanics and the elderly. According to new research reported in the April 15, 2014 issue of the Annals of Internal Medicine, diabetes increased from 6 percent to 10 percent in the past two decades and pre-diabetes also doubled ...

Drought hormones measured

2014-04-15
Stanford, CA—Floods and droughts are increasingly in the news, and climate experts say their frequency will only go up in the future. As such, it is crucial for scientists to learn more about how these extreme events affect plants in order to prepare for and combat the risks to food security that could result. Like animals, plants have hormones that send chemical signals between its cells relaying information about the plant's development or interactions with the outside world. One particular way in which plants use hormone signals is in reaction to drought or soil saltiness. ...

Scholars propose new standards for gauging muscle decline in older adults

2014-04-15
Sarcopenia — the age-related loss of muscle mass and strength — may put up to 50 percent of seniors at greater risk for disability, yet there is no consensus within the medical community for how this condition should be measured. However, a new collection of articles appearing in The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences (volume 69, number 5) lays out an empirically derived set of criteria for diagnosing sarcopenia. These recommendations are a result of the Foundation for the National Institutes of Health Biomarkers Consortium Sarcopenia ...

LAST 30 PRESS RELEASES:

QUT scientists create material to turn waste heat into clean power

Major new report sets out how to tackle the ‘profound and lasting impact’ of COVID-19 on cardiovascular health

Cosmic crime scene: White dwarf found devouring Pluto-like icy world

Major report tackles Covid’s cardiovascular crisis head-on

A third of licensed GPs in England not working in NHS general practice

ChatGPT “thought on the fly” when put through Ancient Greek maths puzzle

Engineers uncover why tiny particles form clusters in turbulent air

GLP-1RA drugs dramatically reduce death and cardiovascular risk in psoriasis patients

Psoriasis linked to increased risk of vision-threatening eye disease, study finds

Reprogramming obesity: New drug from Italian biotech aims to treat the underlying causes of obesity

Type 2 diabetes may accelerate development of multiple chronic diseases, particularly in the early stages, UK Biobank study suggests

Resistance training may improve nerve health, slow aging process, study shows

Common and inexpensive medicine halves the risk of recurrence in patients with colorectal cancer

SwRI-built instruments to monitor, provide advanced warning of space weather events

Breakthrough advances sodium-based battery design

New targeted radiation therapy shows near-complete response in rare sarcoma patients

Does physical frailty contribute to dementia?

Soccer headers and brain health: Study finds changes within folds of the brain

Decoding plants’ language of light

UNC Greensboro study finds ticks carrying Lyme disease moving into western NC

New implant restores blood pressure balance after spinal cord injury

New York City's medical specialist advantage may be an illusion, new NYU Tandon research shows

Could a local anesthetic that doesn’t impair motor function be within reach?

1 in 8 Italian cetacean strandings show evidence of fishery interactions, with bottlenose and striped dolphins most commonly affected, according to analysis across four decades of data and more than 5

In the wild, chimpanzees likely ingest the equivalent of several alcoholic drinks every day

Warming of 2°C intensifies Arctic carbon sink but weakens Alpine sink, study finds

Bronze and Iron Age cultures in the Middle East were committed to wine production

Indian adolescents are mostly starting their periods at an earlier age than 25 years ago

Temporary medical centers in Gaza known as "Medical Points" (MPs) treat an average of 117 people daily with only about 7 staff per MP

Rates of alcohol-induced deaths among the general population nearly doubled from 1999 to 2024

[Press-News.org] Brain changes are associated with casual marijuana use in young adults
Preliminary study suggests effects of drug even in those who are not addicted