Shrunken structures inside the brains of heavy marijuana users might explain the stereotype of the \u201cpothead,\u201d brain researchers report.<\/p>\n
Northwestern University scientists studying teens who were marijuana smokers or former smokers found that parts of the brain related to working memory appeared diminished in size \u2014 changes that coincided with the teens\u2019 poor performance on memory tasks.<\/p>\n
\u201cWe observed that the shapes of brain structures related to short-term memory seemed to collapse inward or shrink in people who had a history of daily marijuana use when compared to healthy participants,\u201d said study author Matthew Smith. He is an assistant research professor in psychiatry and behavioral sciences at the Northwestern University Feinberg School of Medicine, in Chicago.<\/p>\n
The shrinking of these structures appeared to be more advanced in people who had started using marijuana at a younger age. This suggests that youngsters might be more susceptible to drug-related memory loss, according to the study, which was published in the Dec. 16 issue of the journal Schizophrenia Bulletin.\u00a0 \u201cThe brain abnormalities we\u2019re observing are directly related to poor short-term memory performance,\u201d Smith said. \u201cThe more that brain looks abnormal, the poorer they\u2019re doing on memory tests.\u201d<\/p>\n
The paper is provocative because the participants had not been using marijuana for a couple years, indicating that memory problems might persist even if the person quits smoking the drug, said Dr. Frances Levin, chairman of the American Psychiatric Association\u2019s Council on Addiction Psychiatry.<\/p>\n
At the same time, Levin cautioned that the paper presents a chicken-or-egg problem. It\u2019s not clear whether marijuana use caused the memory problems or people with memory problems tended to use marijuana.\u00a0 \u201cThe big $64,000 question is [whether] these memory problems predate the marijuana use,\u201d Levin said.<\/p>\n
The study focused on nearly 100 participants sorted into four groups: healthy people who never used pot, healthy people who were former heavy pot smokers, people with schizophrenia who never used pot and schizophrenics who were former heavy pot users.<\/p>\n
Researchers used MRI scans to study the structure of participants\u2019 brains. Both healthy and schizophrenic marijuana users showed shrinkage of regions deep in the brain that are associated with memory.\u00a0 \u201cWe found both of the marijuana-use groups had these parallel brain abnormalities,\u201d Smith said.\u00a0 Tests of working memory further found that marijuana users scored lower compared with non-users.<\/p>\n
Working memory is the ability to remember and process information in the moment and, if needed, transfer it to long-term memory. Poor working memory can lead to poor academic performance and problems with everyday life.<\/p>\n
Healthy people who never used marijuana scored 37 times better, on average, than healthy users who had smoked in the past on memory tests, while \u201cclean\u201d schizophrenics scored nearly four times better than schizophrenic marijuana users.<\/p>\n
The study confirms earlier findings that showed memory loss in young marijuana users, said Dr. Scott Krakower, assistant unit chief of psychiatry at Zucker Hillside Hospital in Glen Oaks, N.Y.\u00a0\u00a0 But Krakower said more work needs to be done before it\u2019s proven that marijuana actually causes changes in the brain. \u201cFuture research needs to be done to<\/p>\n
verify the implications of marijuana use on the \u2026 structure of the brain,\u201d he said. \u201cIt needs to be studied in a group of people over a period of time.\u201d<\/p>\n
Dr. Mitch Earleywine, a professor of psychology and director of clinical training at the State University of New York at Albany, agreed that the results need to be replicated.<\/p>\n
\u201cBrain structural studies often look at every single spot and then capitalize on the ones that are significant by chance,\u201d said Earleywine, author of the book Understanding Marijuana. \u201cWe\u2019ve had no structural deficits in folks who started using as adults, so researchers went to adolescents.\u201d<\/p>\n
Earleywine said marijuana users have been shown to perform more poorly on memory tests due to the stress they endure taking such tests.\u00a0 \u201cIf you can imagine going into a lab to take a memory test because you\u2019ve been selected for your cannabis use, then a bevy of white-coated folks who might think that cannabis use impairs memory start giving you memory tests, you might not do so well,\u201d he said. \u201cWe\u2019ve found this for males in my lab.\u201d<\/p>\n
The Northwestern study also noted that these changes in brain structure are similar to those associated with having schizophrenia.\u00a0 \u201cIf someone has a family history of schizophrenia, they are increasing their risk of developing schizophrenia if they abuse marijuana,\u201d Smith said.\u00a0\u00a0 But Krakower said that assertion might be a stretch.\u00a0 \u201cI thought that was a little bit of a jump,\u201d he said. \u201cWe know people with schizophrenia use marijuana. It\u2019s going to be very hard to say that someone has schizophrenia because they used marijuana. That\u2019s going to be hard to prove.\u201d<\/p>\n
The Northwestern research is supported by grants from the U.S. National Institutes of Health.<\/p>\n
More information For more information on marijuana, visit the U.S. National Institute on Drug Abuse.<\/p>\n
Source: news.health.com\u00a0 16th December 2013<\/em><\/p>\n","protected":false},"excerpt":{"rendered":" Shrunken structures inside the brains of heavy marijuana users might explain the stereotype of the \u201cpothead,\u201d brain researchers report. Northwestern University scientists studying teens who were marijuana smokers or former smokers found that parts of the brain related to working memory appeared diminished in size \u2014 changes that coincided with the teens\u2019 poor performance on […]<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[63,30,68,19],"tags":[],"class_list":["post-9143","post","type-post","status-publish","format-standard","hentry","category-brain-and-behaviour","category-cannabis-marijuana","category-drug-use-various-effects","category-usa"],"_links":{"self":[{"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/posts\/9143","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/comments?post=9143"}],"version-history":[{"count":0,"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/posts\/9143\/revisions"}],"wp:attachment":[{"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/media?parent=9143"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/categories?post=9143"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/tags?post=9143"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}