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  1. chillinwill
    The effects of daily cannabis use on teenage brains is worse than originally thought and the long-term effects appear to be irreversible, new research from McGill University suggests.

    The study, by Dr. Gabriella Gobbi, a psychiatric researcher from the Research Institute of the McGill University Health Centre, suggests that daily cannabis consumption can lead to depression and anxiety.

    The new study, published in Neurobiology of Disease, suggests that the reputed "soft" drug has an impact on serotonin and norepinephrine, compounds which help control mood and anxiety.

    Her research team observed that 18 rats exposed to cannabis had decreased levels of serotonin, which affects mood; and higher levels of norepinephrine, which makes one more susceptible long-term to stress.

    "These permanent changes in the brain are also linked to certain mental illnesses, like schizophrenia," Gobbi said in an interview Thursday.

    "And we showed that even if we stopped the cannabis use at the end of adolescence, the changes were still detectable in adulthood."

    While past epidemiological studies have shown how cannabis consumption can affect behaviour in some teenagers, Gobbi said the new study demonstrates that the effects are more devastating in teens compared to adults.

    "Our study is one of the first to focus on the neurobiological mechanisms at the root of this influence of cannabis on depression and anxiety in adolescents," she said.

    Gobbi says the study reveals that because serotonin and norepinephrine systems are still in development during adolescence, cannabis interfere with their development.

    "We don't know if some subjects would be more at-risk than others, including adults," said the McGill professor.

    Gobbi said she will be observing a group of young human marijuana smokers to continue her research.

    December 17, 2009
    Breitbart
    http://www.breitbart.com/article.php?id=cp_x12179A.xml&show_article=1

Comments

  1. chillinwill
    Re: The effects of daily cannabis use on teenage brains is worse than originally thou

    Canadian teenagers are among the largest consumers of cannabis worldwide. The damaging effects of this illicit drug on young brains are worse than originally thought, according to new research by Dr. Gabriella Gobbi, a psychiatric researcher from the Research Institute of the McGill University Health Centre.

    The new study, published in Neurobiology of Disease, suggests that daily consumption of cannabis in teens can cause depression and anxiety, and have an irreversible long-term effect on the brain.

    "We wanted to know what happens in the brains of teenagers when they use cannabis and whether they are more susceptible to its neurological effects than adults," explained Dr. Gobbi, who is also a professor at McGill University. Her study points to an apparent action of cannabis on two important compounds in the brain -- serotonin and norepinephrine -- which are involved in the regulation of neurological functions such as mood control and anxiety.

    "Teenagers who are exposed to cannabis have decreased serotonin transmission, which leads to mood disorders, as well as increased norepinephrine transmission, which leads to greater long-term susceptibility to stress," Dr. Gobbi stated.

    Previous epidemiological studies have shown how cannabis consumption can affect behaviour in some teenagers. "Our study is one of the first to focus on the neurobiological mechanisms at the root of this influence of cannabis on depression and anxiety in adolescents," confirmed Dr. Gobbi. It is also the first study to demonstrate that cannabis consumption causes more serious damage during adolescence than adulthood.

    Dr. Gabriella Gobbi is a researcher at the neuroscience axis of the Research Institute of the McGill University Health Centre and also a psychiatrist and associate professor at the Department of Psychiatry, McGill University.

    This study was funded by a grant from The Canadian Psychiatric Research Foundation (CPRF)

    This article was co-authored by Dr. Francis Rodriguez Bambico; Ms. Nhu-Tram Nguyen, and Mr. Noam Katz from from IR-MUHC and the Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University.

    December 17, 2009
    Science Daily
    http://www.sciencedaily.com/releases/2009/12/091217115834.htm
  2. chillinwill
    Re: The effects of daily cannabis use on teenage brains is worse than originally thou

    Can we have some science reporting with integrity, please?

    There’s nothing like marijuana to completely unhinge the integrity of science reporting. Any study that reveals some bit of information that could be interpreted in a way that could lead in a direction of eventually showing harmful effects about marijuana is hyped as if it had been proved conclusively.

    One of the things that is most potentially controversial about marijuana is its effect on children and developing brains. Now, those of us in drug policy reform are all for more research, and if it does harm developing brains, we want to know it. But we want real science, real research, real results. Quite frankly, if it’s true, it makes our argument stronger — after all, we’re the ones for regulating. The criminals that work under the prohibition regime don’t check I.D.s.

    And yet, a lot of “science” reporting seems just intended to scare people.

    Take this article in Science Daily: Cannabis Damages Young Brains More Than Originally Thought, Study Finds

    Canadian teenagers are among the largest consumers of cannabis worldwide. The damaging effects of this illicit drug on young brains are worse than originally thought, according to new research by Dr. Gabriella Gobbi, a psychiatric researcher from the Research Institute of the McGill University Health Centre. The new study, published in Neurobiology of Disease, suggests that daily consumption of cannabis in teens can cause depression and anxiety, and have an irreversible long-term effect on the brain.

    Hmmm… OK. Sounds serious. I should look into this. I wonder what kind of research was employed…. Wait, let me read the article again. I still wonder what kind of research was employed! There’s all this talk about teenagers and adolescents, but nothing about how they studied them.

    So I went to the study. But…. but the researchers didn’t study teenagers. Not one. They studied adolescent rats.

    The pathophysiological neural mechanism underlying the depressogenic and anxiogenic effects of chronic adolescent cannabinoid use may be linked to perturbations in monoaminergic neurotransmission. We tested this hypothesis by administering the CB1 receptor agonist WIN55,212-2, once daily for 20 days to adolescent and adult rats, subsequently subjecting them to tests for emotional reactivity paralleled by the in vivo extracellular recordings of serotonergic and noradrenergic neurons. Chronic adolescent exposure but not adult exposure to low (0.2 mg/kg) and high (1.0 mg/kg) doses led to depression-like behaviour in the forced swim and sucrose preference test, while the high dose also induced anxiety-like consequences in the novelty-suppressed feeding test. Electrophysiological recordings revealed both doses to have attenuated serotonergic activity, while the high dose also led to a hyperactivity of noradrenergic neurons only after adolescent exposure. These suggest that long-term exposure to cannabinoids during adolescence induces anxiety-like and depression-like behaviours in adulthood and that this may be instigated by serotonergic hypoactivity and noradrenergic hyperactivity.

    Notice that their test results “suggest” certain vague conclusions. Yet in the ScienceDaily article, the study finds that cannabis damages brains. And yes, results in rats can suggest that certain things may be true in humans as well, but it certainly doesn’t prove it.

    It would be nice to have integrity in science reporting. It would also be nice to have scientific researchers to have the integrity to refuse to feed these media morons.

    December 17, 2009
    Drug Warrant
    http://www.drugwarrant.com/2009/12/can-we-have-some-science-reporting-with-integrity-please/
  3. mbarnes0
    Re: The effects of daily cannabis use on teenage brains is worse than originally thou

    TEEN MARIJUANA USERS MORE LIKELY TO GET DEPRESSED

    Study Finds Daily Smokers More Susceptible To Anxiety As Adults

    Teenagers who smoke marijuana on a daily basis cause damage to their developing brains, making them more susceptible to depression and anxiety in adulthood, a new McGill University study suggests.

    The finding is particularly significant in the Canadian context, given previous research showing that more teens in this country consume cannabis than do adolescents in the U.S. or Europe.

    "Just because marijuana is a plant doesn't mean it's harmless," said Gabriella Gobbi, one of the study's co-authors.

    "Our study demonstrated that the cannabinoid, when consumed daily during adolescence, can induce a permanent change in the brain."

    Scientists at the Research Institute of the McGill University Health Centre experimented on adolescent and adult lab rats. They discovered that when they exposed the rats for 20 days to cannabinoids -- the active ingredient in marijuana -- only the adolescent rats were adversely affected. This suggests that the adolescent brain -- since it is still developing -- is particularly vulnerable to chronic drug use.

    The researchers observed a decrease in serotonin levels in the brains of the adolescent rats. Serotonin is a neurotransmitter that plays a role in emotional perception.

    Conversely, the researchers noticed an increase in norepinephrine levels. Norepinephrine plays a key role in the so-called fight-or-flight response, and increased levels could make one more anxious.

    The findings were published in the journal Neurobiology of Disease. Although the research was carried out on lab rats, Gobbi said one can assume the same effects on the human brain. Still, Gobbi plans to carry out a different type of study on humans to confirm the effects of the animal trials. Gobbi cited research by the Public Health Agency of Canada in 2004 that showed that 42.7 per cent of Canadian adolescents had tried marijuana compared with 40 per cent of teens in the United States and 35 per cent of teens in Europe.

    Earlier research by Gobbi has also challenged some of the myths surrounding marijuana. In 2007, she published a study that found that although marijuana does act as an anti-depressant in the short-term, it produces the opposite effect in the long run.

    Fri, 18 Dec 2009
    Aaron Derfel
    Ottawa Citizen
    http://www.mapinc.org/drugnews/v09/n1130/a02.html
  4. staples
    Re: The effects of daily cannabis use on teenage brains is worse than originally thou

    I uploaded the paper that these articles seem centered around (I also saw the older publication by Gobbi on the anti-depressant effects of marijuana, if someone would like to see that as well).

    Chronic exposure to cannabinoids during adolescence but not during adulthood impairs emotional behaviour and monoaminergic neurotransmission
    Bambico, F. R., Nguyen, N., Katz, N., & Gobbi, G. (n.d.).
    Neurobiology of Disease, In Press, Uncorrected Proof. doi: 10.1016/j.nbd.2009.11.020.

    It's unfortunate that sensational news sources will simply jump to the conclusion that this research definitely also applies to human adolescents. However, we shouldn't simply ignore the possibility, either.
  5. Gradient
    Re: The effects of daily cannabis use on teenage brains is worse than originally thou

    I strongly agree. Accordingly, if anyone is interested, below is a very short summary of findings in this paper. It's important to note that most of this data is based upon behavioral analysis in various tasks such as maze-navigating, forced swimming, sucrose preference. All data from these evaluations is therefore entirely correlative - and though it may indeed indicate potential interactions in humans, it certainly isn't firm corroboration of any such interactions. There is indeed electrophysiological and histological analyses as well, however - so this is indeed a pretty aggressive study.

    Chronic exposure to cannabinoid agonist WIN55,212-2 does not increase anxiety in the maze-test or open field test. It did, however, enhance anxiety as measured by inhibition of ingestion and approach to food when in anxiety-inducing conditions. The agonist appears to reduce stress-coping behaviors, promote anhedonia, and noradrenergic neural activity was enhanced only after chronic exposures to the cannabinoid agonist. Interestingly, the compound dose-dependently reduced the activity in serotonergic circuits. The authors conclude that persistent exposure to cannabinoid agonists - specifically during adolescence - can influence the development of monoaminergic mood-regulating circuits, with behavioral repercussions manifested further in development. Here are some relevant statements:

    Very interesting study. The last statement is important, as they propose that the implications of cannabinoid-influenced monoaminergic development may only be realized later in adulthood manifested as enhanced vulnerabilities to depression and anxiety.
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