Navigation Links
Teen Marijuana Use Might Have Lasting Effects on Mood, Anxiety
Date:12/23/2009

Rat study found troubling changes in levels of key brain chemicals well into adulthood

WEDNESDAY, Dec. 23 (HealthDay News) -- Marijuana use among teens may trigger neurological changes in the developing brain that lead to increased anxiety and stress levels that could persist into adulthood, new animal research suggests.

Although the finding stems solely from work conducted with adolescent and adult lab rats -- not yet replicated among humans -- the work suggests that certain troublesome changes in levels of the key brain chemicals serotonin and norepinephrine may linger long after marijuana use ceases.

"Here, the goal was simply to understand the neurological mechanism that could be underlying the specific phenomenon of depression and anxiety observed in previous studies among adolescents chronically exposed to cannabis," explained study author Dr. Gabriella Gobbi, a psychiatric researcher at the Research Institute of the McGill University Health Centre in Montreal.

"And what we found with the animals we worked with is that when those that were exposed to cannabis as adolescents became adults they had low serotonin activity, which is related to depressive behavior, and high norepinephrine levels, which is related to an increase in anxiety and stress," Gobbi continued.

"This means," she cautioned, "that cannabis exposure when young seems to cause changes in the adult brain. And these changes could perhaps be irreversible, even if you stop consuming cannabis."

The study findings were released online Dec. 5 in advance of publication in an upcoming print issue of Neurobiology of Disease.

The authors note that the main ingredient in marijuana -- delta-9-tetrahydrocannabinol (THC) -- has previously been identified as having an impact on receptors in the brain that regulate cognition and emotion.

In addition, they point out that the adolescent brain is perhaps particularly sensitive to both drug use and related stress, given that this is the pre-adult period during which the brain and its neurochemical composition undergoes extensive reshaping and reorganizing.

To assess the role cannabis may play on adolescent brain development, for 20 days -- a period characterized as "prolonged exposure" -- adolescent rats were given daily injections of either a low-dose (0.2 milligrams/kilograms) or high-dose (1.0 milligrams/kilograms) of cannabis. For comparison, a group of adult rats underwent a similar regimen.

Following cannabis exposure, both the adolescent and adult groups went 20 days drug-free to allow the effects of drug withdrawal to dissipate, as well as to allow for a wide range of cognitive testing to gauge the long-term effects of cannabis exposure on task execution and mood.

The authors noted that by the conclusion of the 20-day waiting period, the previously adolescent rats were effectively adults.

The team found that chronic exposure to cannabis during adolescence does appear to provoke abnormal emotional activity into adulthood, typified by the onset of depression, poorer social interaction, heightened anxiety and increased stress.

What's more, Gobbi and her colleagues also found a drop in serotonin levels in the adult brain following either low- or high-dose adolescent ingestion and an increase in norepinephrine levels following high-dose exposure.

Rats who had already reached adulthood when chronically exposed to cannabis, however, appeared to experience far less of the detrimental emotional reactions found among adolescent rats. Indeed, adult rats, they observed, seemed to be able to readily cope with, and even overcome, most of the neurological impairments that arose as a result of cannabis exposure.

"We were a little bit surprised by our findings because we didn't expect to see such a strong effect on the adult brain from adolescent usage. It was a very significant effect," said Gobbi.

"So, in general, I think that what people should take away from this work," she advised, "is that just because it's a plant it doesn't mean that marijuana is harmless. It's a pharmacologically active drug, and it must be used with awareness."

For his part, however, Dr. Adam Bisaga, an addiction psychiatrist at New York State Psychiatric Institute, minimized the relevance of the findings.

"I think the translational value of this research is very limited insofar as what the clinical relevance to humans might be," Bisaga cautioned. "It's always very difficult to translate from animal models to humans. Yes, there is some indication that this may be of importance to humans. But most of the data with patients that I am familiar with suggests that most of these cannabis-exposure deficits are reversible. So, for the time being I'm not that impressed, although it's certainly something to further study in humans," he added.

"This is not new," he noted. "Clinicians know well that exposure to large amounts of cannabis in adolescence may produce enduring changes in emotional functioning and reactivity in vulnerable individuals, such as difficult-to-treat anxiety and depressive symptoms. What this paper does is to try to characterize more precisely the components of this syndrome using animal models of emotional reactivity."

More information

For more on marijuana use and its effect on the brain, visit the U.S. National Institute on Drug Abuse.



SOURCES: Gabriella Gobbi, M.D., Ph.D., psychiatric researcher, Research Institute of the McGill University Health Centre, Montreal; Adam Bisaga, M.D., assistant professor, psychiatry, Columbia University, and addiction psychiatrist, New York State Psychiatric Institute, New York City; Dec. 5, 2009, Neurobiology of Disease, online


'/>"/>
Copyright©2009 ScoutNews,LLC.
All rights reserved

Related medicine news :

1. Pot and pop: New research finds stronger link between music and marijuana use among teens
2. Marijuana, Alcohol Addiction May Share Genes
3. Marijuana Use No Longer Dropping Among U.S. Teens
4. Medithrive Voted #1 Medicinal Marijuana Dispensary in Bay Area
5. Review Finds Marijuana May Help MS Patients
6. Parental Monitoring Can Curb Teen Marijuana Use
7. The straight dope: Studies link parental monitoring with decreased teen marijuana usage
8. Commerce Online Announces Agreement With RedFin Network For Medical Marijuana Dispensary Pre-Paid Loyalty Card Program
9. Faith-Based Leaders and Community Activists Converge on State Capitol to Oppose Legalized Marijuana
10. Arizona Medical Marijuana Policy Project, Sponsors of 2010 Medical Marijuana Ballot Initiative in Arizona, Cheer Obama Administration Action
11. U.S. Relaxes Opposition to Medical Marijuana
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:10/13/2017)... ... ... “America On The Brink”: the Christian history of the United States and ... of published author, William Nowers. Captain Nowers and his wife, Millie, have six ... years in the Navy. Following his career as a naval aviator and carrier ...
(Date:10/12/2017)... (PRWEB) , ... October 12, 2017 , ... ... products to meet the demand of today’s consumer and regulatory authorities worldwide. From ... probiotic experts and tested to meet the highest standard. , These products ...
(Date:10/12/2017)... ... October 12, 2017 , ... ... that we intend to develop to enable prevention of a major side effect ... hearing loss, especially in pediatric patients. For cisplatin, hearing loss is FDA listed ...
(Date:10/12/2017)... (PRWEB) , ... October 12, 2017 , ... On Saturday, ... a treadmill relay – Miles by Moonlight to raise money for the American Heart ... or more. , Teams will work together to keep their treadmills moving for ...
(Date:10/12/2017)... ... October 12, 2017 , ... Vohra Chief ... advancements to physician colleagues, skilled nursing facility medical directors and other clinicians at ... of Wound Care." , "At many of these conferences we get to educate ...
Breaking Medicine News(10 mins):
(Date:10/11/2017)... IRVING, Texas , Oct. 11, 2017  Caris ... science focused on fulfilling the promise of precision medicine, ... Institute has joined Caris, Precision Oncology Alliance™ (POA) as ... leading cancer centers, the St. Jude Crosson Cancer Institute ... to advance the use of tumor profiling, making cancer ...
(Date:10/10/2017)... received FDA 510(k) clearance in May 2017 for its highly anticipated ... for endoscopy environments. An innovative secondary monitor solution, ZeroWire Mobile ... the improvement of patient outcomes, procedural efficiency, and the lowering of ... ... By ...
(Date:10/5/2017)... 2017  In response to the nationwide opioid ... Surgeons (AAOMS) released prescribing recommendations that urge ibuprofen ... as a first-line therapy to manage a patient,s ... Recognizing the value and importance of ... Prescribing: Acute and Postoperative Pain Management" stresses that ...
Breaking Medicine Technology: