The world of legal recreational cannabis has many people worried about how safe this drug can be. Many claim that since it is natural it cannot be as harmful as other drugs as well as providing other claims as to its safety. However, a new study by a group of researchers at Northwestern University seeks to demonstrate that there are some negative effects of cannabis use in adolescents that mimic changes in the brain that are similar to schizophrenia especially with their effects on memory.
This is quite an interesting new area to explore, especially with the new push for legalization in many states. This is because since legalized recreational use of Cannabis in some states is so recent there has not been much time or as much access to data on the effects of usage on adolescents and teens.
This lack of time form recreational legalization for easier study has not prevented some research from being done. Some of the result of previous research on Cannabis use on memory show that adolescents and young adults that have used Cannabis tend to score lower on long term memory tests than non users by about 18 percent. This deficit tends to be associated with episodic memory which is the type of memory that involves being able to recall specific things about your own past. However, the understanding of why these deficits in memory occur has not been fully explored which is why these researchers at Northwestern carried out their study.
To determine the effect of Cannabis on memory the researchers chose to examine the area known to be associated with long term memory, the Hippocampus. This area of the brain has also been known to be affected by many neurological conditions such as Schizophrenia.
To test whether or not adolescent cannabis use has similar effects on the brain the researchers decided to use Magnetic Resonance brain mapping to see if there were any structural differences in the hippocampus between past users of Cannabis to non users as well as schizophrenic users and non users of Cannabis. The researchers found that the same areas of the hippocampus that are deformed as a result of schizophrenia are also the same areas affected in the hippocampus of adolescent users of Cannabis that suffer memory deficits. The main effect that was seen with relation to the structure of the hippocampus was that it became less ridged and became smoother decreasing the overall surface area. This change, seen below, is what the researchers believe to be the cause of decreased memory. In addition, the results of this study also agree with the results of a 2013 study linking Cannabis use with relation to likelihood of mental disorders such as schizophrenia since it demonstrates that there are similar brain changes.
Figure 1 from Smith et al 2015
This figure shows the change in hippocampus structure
between control hippocampus vs cannabis use hippocampus (row 1) schizophrenic
vs control (row 2) and schizophrenic vs cannabis use.
With such strong evidence relating adolescent Cannabis use to severe hippocampus structure changes mimicking schizophrenia it makes sense that many people want stronger restrictions on recreational usage of Cannabis. Many try to claim that the access that adults have to recreational Cannabis will affect the usage of adolescents, therefore the access adults have to Cannabis should be restricted. However, the use of other drugs such as alcohol, during adolescence has also been shown to be detrimental to brain function in adulthood. This suggests that it is maybe not solely cannabis that is the major harm to adolescent brains but rather the use of any drug that affects the brain on one that is still developing. This would cause the stress of drug management to go from prohibiting all drugs, to ensuring that relatively safe drugs such as tobacco, alcohol, and some would argue cannabis, are only being used by adults whose brains are developed enough to handle such drugs without suffering major changes.
For more information on this topic check out the sources below:
Drug Use in Adolescents
http://ajp.psychiatryonline.org/doi/10.1176/appi.ajp.160.6.1041
Chambers, R. (n.d.). Developmental Neurocircuitry of Motivation in Adolescence: A Critical Period of Addiction Vulnerability. American Journal of Psychiatry, 1041-1052.
Cannabis and Schizophrenia
Smith, M. (2015). Cannabis-Related Episodic Memory Deficits and Hippocampal Morphological Differences in Healthy Individuals and Schizophrenia Subjects.Hippocampus. Retrieved March 12, 2015, from http://onlinelibrary.wiley.com/enhanced/doi/10.1002/hipo.22427/
Chadwick, B., Miller, M., & Hurd, Y. (n.d.). Cannabis Use during Adolescent Development: Susceptibility to Psychiatric Illness. Frontiers in Psychiatry.
While it is very interesting to learn that Cannabis use is potentially harmful the the brain, I think it is also important to address the addictive property of Cannabis. As far as I know, Cannabis does not exhibit physical addictive property, meaning one would not get withdrawal symptom when quitting Cannabis use. As mentioned in the blog, Cannabis is not the only harmful drug. Other legal drugs like alcohol and tobacco are also harmful to the body. As such, I agree that it is shaky to base the argument that Cannabis should be banned on the fact that it potentially causes harm to the body.
ReplyDeleteAre the changes to the brain due to cannabis use permanent? I would be interested to see the comparison between the brain of a heavy cannabis user, a non user, and someone who used to use heavily but no longer does (perhaps one year, five years, and ten years after stopping use). The body has an amazing ability to recover from stressors, and I wonder if this extends to cannabis use. This might not be the case if the effects were felt during development, but I think that with the legalization of this drug it is important to look at not only long term effects, but also the hope of recovery for those who may suffer negative consequences.
ReplyDeleteI would imagine that for this study, they didn't give adolescents Cannabis and then scan their brains after extended use.
ReplyDeleteSo, you mention that other drugs and alcohol use in adolescents also causes brain damage. I imagine that the adolescents this study chose were adolescents that were already smoking marijuana. But did they account for whether those adolescents were drinking alcohol or whether they were using other drugs? I feel unless they found adolescents that were ONLY using marijuana, the true effects of marijuana in adolescents is uncertain. I believe the that early use of drugs is harmful, but I'm skeptical until I read and trust the methods used.
As for my opinion on the legalization of marijuana, I'm a cautious liberal. I think it's okay, but laws need to be in place to prevent misuse (such as minimum age and limited purchase).
Also, where(or at what age) is considered the line between adolescence and adulthood?
I agree with Rehman on this one. I think that it would be interesting to see the results of a study examining brain development in adolescents where cannabis use is the sole variable. It may be a challenge to test only this with a significant sample size, but it could be valuable to conduct a study looking at broad drug use (alcohol, cannabis, stimulants etc.) in adolescents and examine memory as well as brain structure. These results could then help people decide whether or not they wish to use or try these substances.
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ReplyDeleteI find it interesting that so often studies focused on cannabis and extended use tend to find few concrete links between the drug and negative side effects, yet they generally conclude with a caveat of condemn the drug's use. It seems like the majority of legitimate studies done on cannabis, which must be approved by the US government, are skewed before they even begin. These studies are always looking for the smoking gun to group marijuana in with more serious and dangerous drugs, and it is rare that we see legitimate scientific studies on the efficacy of cannabis as a treatment for a myriad of serious conditions. All circumstantial evidence has shown that long term cannabis users are healthy and work at the same or similar levels of brain function as non users. It seems to me that anytime a group of scientists enter a study with predetermined goals, they are going to achieve them through selective data use and assumptive language. I would urge those who see studies like this to examine the methods and funding for that study before making a judgement on its legitimacy.
ReplyDeleteI completely agree with Connor on this point. The methods behind this paper fail to address an assortment of confounding factors, including socioeconomic class and predisposition to trying marijuana based on intellectual grouping. Basically, these researchers are saying that marijuana use is detrimental to cognitive health, but all that they've shown is that the two are correlated. One of the most important lessons in science is that correlation does not imply causation, so until we see some harder evidence of before and after brain damage, we should reject this article as grounds for marijuana restriction.
DeleteI find it interesting that so often studies focused on cannabis and extended use tend to find few concrete links between the drug and negative side effects, yet they generally conclude with a caveat of condemn the drug's use. It seems like the majority of legitimate studies done on cannabis, which must be approved by the US government, are skewed before they even begin. These studies are always looking for the smoking gun to group marijuana in with more serious and dangerous drugs, and it is rare that we see legitimate scientific studies on the efficacy of cannabis as a treatment for a myriad of serious conditions. All circumstantial evidence has shown that long term cannabis users are healthy and work at the same or similar levels of brain function as non users. It seems to me that anytime a group of scientists enter a study with predetermined goals, they are going to achieve them through selective data use and assumptive language. I would urge those who see studies like this to examine the methods and funding for that study before making a judgement on its legitimacy.
ReplyDeleteI find this post very interesting and it makes me wonder if long term use will permanently damage a persons brain or even if just some use of it can have long- term effects of certain parts of someones brain. I agree with some of the previous comments that seeing a study comparing users and non-users would be beneficial and help to further the studies of this. Depending on what these results would be, I think that only with results they should make restrictions if there would need to be any.
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ReplyDeleteIn my psychopharmacology class, I just finished reading about the effects of cannabis on the brain. THC, the psychoactive component of cannabis, is seen to interfere with the brain's endogenous endocannabinoid system. With the interference of neurochemicals in the brain, I agree that it could interfere the development of an adolescent's brain and could predispose them to future drug addictions and psychiatric disorders such as schizophrenia. This scientific evidence and future studies should be taken into consideration for policymakers in the future when considering the legalization of marijuana across states, especially in terms of age restrictions.
ReplyDeleteI don't think there's any question that there are some negative consequences to cannabis, especially in relation to memory loss. I'd like to see a long term study done comparing the brains of frequent marijuana smokers in their adolescent years all the way into adulthood compared with non smokers. This will give us a better idea of the long term implications of marijuana. Particularly, whether or not marijuana usage can negatively impact the brain long term, and to what extent. As of now, I don't think there's really a serious enough reason to keep it illegal. Alcohol usage is much more taboo, and yet has shown to have serious implications such as drunk driving, mental illness, addiction, and family violence. As of now, the implications of marijuana do not seem so severe to keep it illegal, though I'd like to see more of these long term studies done to fully understand the risks associated with usage.
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