Navigation Links
Marijuana May Shrink Parts of the Brain
Date:6/2/2008

Drug can affect memory and result in early psychotic symptoms, researchers say

MONDAY, June 2 (HealthDay News) -- People who use marijuana for a long time can develop abnormalities in their brains, Australian researchers report.

Although growing literature suggests that long-term marijuana use is associated with a wide range of adverse health consequences, many people believe it is relatively harmless and should be legalized, the researchers noted.

"However, this study shows long-term, heavy cannabis use causes significant brain injury, memory loss, difficulties learning new information, and psychotic symptoms, such as delusions of persecution [paranoia], delusions of mind-reading, and bizarre social behaviors in even non-vulnerable users," said lead researcher Murat Yucel, from the ORYGEN Research Centre and the Neuropsychiatry Centre at the University of Melbourne.

This new evidence plays an important role in further understanding the effects of marijuana and its impact on brain functioning, Yucel said. "The study is the first to show that long-term cannabis use can adversely affect all users, not just those in the high-risk categories such as the young, or those susceptible to mental illness, as previously thought," he said.

The report was published in the June issue of the Archives of General Psychiatry.

In the study, Yucel's team did high-resolution MRIs on 15 men who smoked more than five joints a day for more than 10 years. They compared those with scans of 16 men who did not use marijuana.

In addition, all the men took verbal memory tests and were examined for symptoms of psychiatric disorders.

"The more marijuana used, the more these individuals were likely to show reduced brain volumes in the hippocampus and amygdala, as well as being more likely to develop symptoms of psychotic disorders and to have significant memory impairment," Yucel said.

In fact, the hippocampus of marijuana users was 12 percent smaller, and the amygdala was 7.1 percent smaller than among nonusers. In addition, men who used marijuana also had symptoms of psychiatric disorders, Yucel's group found.

The hippocampus is associated with the regulation of emotion and memory, while the amygdala controls fear and aggression.

"There is ongoing controversy concerning the long-term effects of cannabis on the brain," Yucel said. "These findings challenge the widespread perception of cannabis as having limited or no harmful effects on brain and behavior. Although modest use may not lead to significant neurotoxic effects, these results suggest that heavy daily use might indeed be toxic to human brain tissue."

One expert agrees that heavy marijuana use can have negative effects on the brain.

"These findings are not surprising," said Dr. Adam Bisaga, an assistant professor of psychiatry at Columbia University and an addiction psychiatrist at New York State Psychiatric Institute. "Chronic use of large amounts of any substance that is affecting neural transmission will most likely invoke adaptive changes and lead to the reorganization of neural networks, and possibly affect brain structures."

Heavy users of marijuana probably represent only a very small proportion of users, Bisaga said.

"It is not clear if any clinically significant changes can be seen in recreational, infrequent marijuana users, who were not studied here. These findings suggest that public health education, as well as screening, early recognition, and treatment of cannabis dependence, may prevent the progression of the disease and the loss of brain function and related psychiatric complications," Bisaga said.

More information

For more on drug addiction, visit the National Institute on Drug Abuse.



SOURCES: Murat Yucel, Ph.D., ORYGEN Research Centre, Melbourne Neuropsychiatry Centre, University of Melbourne, Australia; Adam Bisaga, M.D., assistant professor, psychiatry, Columbia University, and addiction psychiatrist, New York State Psychiatric Institute, New York City; June 2008, Archives of General Psychiatry


'/>"/>
Copyright©2008 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. RNC RESPONSE TO OBAMA COMMENTS ON MEDICAL MARIJUANA LAWS
2. An Alternative to Medicinal Marijuana
3. Marijuana use on the rise among Ontario adults, CAMH reports
4. Marijuana increases alcohol toxicity in young rats
5. Some moms quit cigarettes, marijuana, alcohol during pregnancy, but dads dont
6. Scripps research team wins $4M grant to study effects of chronic marijuana use
7. Small study shows marijuana does not increase risk of head, neck cancer
8. Drug use trends affect risk of marijuana in deviance prone boys, but not girls
9. Marijuana Use Among MS Patients Raises Risk for Cognitive, Mood Problems
10. Quitting Marijuana Just as Hard as Quitting Cigarettes
11. Heavy marijuana use linked to gum disease
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Marijuana May Shrink Parts of the Brain 
(Date:2/28/2017)... , ... February 28, 2017 , ... Las Vegas Skin ... South Rancho location on Friday, March 10, 2017, 4-7 pm PST. For more than ... this clinic, located in the South Rancho neighborhood, has been renovated to provide medical ...
(Date:2/28/2017)... , ... February 28, 2017 , ... ... decade, has challenges as they transition from military to civilian life. Body image ... two million who experience poorer health and greater occurrence of chronic mental health ...
(Date:2/27/2017)... Houston, Texas (PRWEB) , ... February 27, 2017 ... ... leader in the alternative health care industry, announces Chris Brandl as its New ... has brought vision and purpose to corporations throughout his career. He began his ...
(Date:2/27/2017)... ... , ... The threat of nuclear warfare has long plagued this world. In ... underground testing of nuclear weapons. Years later, when her co-workers began dying, Dot started ... Nuclear Testing,” Clayton exposes the critical decisions made by agencies involved in the nuclear ...
(Date:2/27/2017)... ... February 26, 2017 , ... Miro is the ultimate ... and video system brings songs, movies, TV shows and much more apps for user ... high-definition sound. An immersive view of 1280 x 720 provides crisp images with remarkable ...
Breaking Medicine News(10 mins):
(Date:2/28/2017)... Feb. 27, 2017 Pulmonary drug delivery market ... from USD 36.10 billion in 2016, at a CAGR ... pulmonary route as an alternate route of drug delivery, ... increasing incidence of respiratory diseases such as COPD, asthma, ... growth during the forecast period. However, emerging markets and ...
(Date:2/28/2017)... -- Clarivate Analytics marks the passing of one if its founding fathers, Dr. ... science in the service of scientific and scholarly research. A pioneer in ... that revolutionized the way researchers work with the literature, Garfield passed away ... ... Dr. Eugene Garfield, ...
(Date:2/28/2017)... Research and Markets has announced the addition of the ... their offering. ... The global digestive enzyme supplements market is expected ... regarding the severity of digestive disorders coupled with the need ... the forecast period. The increasing incidence of gastrointestinal tract diseases, ...
Breaking Medicine Technology: