The primary positive effect of cannabis in the general population is probably that it tends to interfere with alcohol consumption, due to excessive sedation. This probably explains the lack of negative population-level effects of cannabis legalization. The most concerning effect of cannabis is its tendency to increase heart rate.
Quite a bit of research is available on the effects of cannabis use — the problem is that people don't read it.
Bronchitis? I've known a lot of marijuana smokers, and I don't recall any of them ever having bronchitis.
>Mental health (associated risk of schizophrenia, depression, anxiety, suicidal ideation, Cannabis use disorder)
Small but >1 ORs for a rare disorder like schizophrenia (base rate ~0.02%) sound scarier than they really are. Many recreational activities are associated with a similar increase in the risk of concussion (base rate ~1%), and yet they are actually recommended for general health. Correlation of recreational drug use with depression/anxiety has a causal direction problem.
Others in this thread have linked studies about the effects on the heart. It remains to be seen what the long-term risk profile is.
That might be the complete slide but it is not the complete picture. This disorder for example causes pretty extreme digestive issues, and it has not been in the medical literature for very long.
some haphazardly chosen references from a 2013 bibliography on the subject, compiled by someone who probably doesn't want her name showing up in an internet forum.
Aryana A, Williams MA. Marijuana as trigger of cardiovascular events: speculation or scientific certainty? Int J Cardiol 2007;118:141-4. https://doi.org/10.1016/j.ijcard.2006.08.001
Bachs L, Morland H. Acute cardiovascular fatalities following cannabis use. Forensic Sci Int 2001;124:200-3.
Cappelli F, Lazzeri C, Gensini GF, Valente S. Cannabis: a trigger for acute myocardial infarction? A case report. J Cardiovasc Med 2008;9:725-728.
Jones RT. Cardiovascular system effects of marijuana. J Clin Pharmacol 2002; 42(11 Suppl.):58S-63.
Sidney S. Cardiovascular consequences of marijuana use. J Clin Pharmacol 2002;42(11 Suppl.):64S-70S. (Found no association.)
Tormey WP. Royal College of Pathologists’ autopsy guidelines on sudden cardiac death: roles for cannabis, cotinine, NSAIDs and psychology. J Clin Pathol 2012;65:187-188.
so there's a starting place to look into it.
maybe the intervening 9 years have demonstrated that it isn't an issue.
> I'm not aware of any proponents of driving while high.
> Again, who's advocating for pregnant women to consume cannabis?
I thought the comment was making clear what was considered a risk, not what is being advocated? People certainly do drive while under the effects of cannabis, I've known a few. I don't know anyone who consumed it while pregnant but I'm sure they do exist.
> I'm not sure anyone thinks you should smoke a bunch of drugs before studying for finals.
> The most concerning effect of cannabis is its tendency to increase heart rate.
Can you please tell me why you think heart rate is more concerning than the psychological effects? Effects which the paper itself mentions and you seem to downplay for some unobvious reason to me.
For me, the difficulty is discerning causation from correlation. Anecdotally I know plenty of cannabis users, and many of them have obvious mental issues. I am interested in knowing the root cause of mental issues, because then we are given the opportunity to affect behaviours to improve people’s lives. A correlation is often little help to anyone but other researchers.
I didn’t read the paper but the abstract didn’t allude to any insight into causation versus correlation. If an abstract of a paper ignores that issue, then I often don’t bother reading, because there is not enough value from studies measuring correlation (for my personal use for any information).
> Anecdotally I know plenty of cannabis users, and many of them have obvious mental issues
If there’s a causal link, I wonder in which direction is more common? I know kids from my neighborhood who now smoke a lot of weed. I think most of them had issues long before trying weed and weed was more of an escape for them, much like booze is for many.
Psychological effects are, in general, reversible. Also, they tend to be dose-dependent, and rather obvious. It's easy to avoid them by limiting consumption. I stopped smoking weed for other reasons, but I didn't really care if my memory formation was impaired after 9 PM. Effects on the heart, on the other hand, can build up for years without much warning, since most people don't get regular EKG.
> Anecdotally I know plenty of cannabis users, and many of them have obvious mental issues
Do they have actual, diagnosed "mental issues", or are you judging that some of their behavior is out of the norm for your experience and thus it must be a mental issue?
Yes, I have acquaintances and friends with diagnosed mental illnesses that smoke weed. Also the same but don’t smoke.
Yes, I have acquaintances and friends with no psychological problems that smoke weed. Also the same but don’t smoke.
Yes, I have acquaintances and friends with “undiagnosed” psychological problems that smoke weed. Also the same but don’t smoke.
No, I am not a professional psychological specialist.
Yes, I have some experiences to be able to make intelligent “non-professional” judgements about psychological problems. My definition of a psychological problem is one where the problem is seriously negatively affecting ones life, and ones skills are not successfully mitigating or correcting the problem. Environmental issues have a part to play in that. My friends and acquaintances have a wide range of ages.
You seem to be fishing for something - perhaps you could have just made your point instead (with caveats).
Disclaimer: I don’t use any form of THC or CBD. No strong reasons against it, just not my thing. I certainly have nothing against those that want or need to take THC or CBD.
Sure, I was fishing. I guess I should have just outright said "Your individual experiences with individuals in a group are invalid when discussing things that can be empirically studied, such as the effects of using cannabis on various groups," and went on with my day.
By the way, labeling an undesirable group with "mental issues" has been done many times in the past, sometimes even with "good" intentions.
A well-designed study may be more revealing, but the individual experiences are legitimate and should not be discarded solely because studies are possible.
A strong enough signal will show in a sample of one.
With a correct model, cause and effect can be predicted without any samples (scientific progress often occurs this way).
And some people’s intuitions are remarkably astute. Albeit there are a lot of people who have incorrect intuitions and don’t know it.
A cannabis example would be strong paranoia after one sesh. More ingrained paranoia (qanon?) that I have seen linked to regular heavy usage doesn’t feel to me to be a stretch of the imagination.
More likely, they probably can't wade thru the noise to find it - search cannabis and health and be prepared to search thru hundreds, if not ten's of thousands of pages of propaganda claiming that it is nothing but good for almost any health condition you have - real or imagined.
If you search PubMed, you will find case reports of other similar incidents. Now, no denying this is an extremely rare adverse effect, but still a quite frightening one. (Also worth stating, many of these reported cases of cannabis-induced psychotic penile self-amputation involve no known history of gender dysphoria.)
I have a feeling that these individuals (I could only find two in my pubmed search) were suffering from schizophrenia, not cannabis-induced psychosis. Maybe you could make the argument that the cannabis caused the schizophrenia, but that's still a different diagnosis.
In the case you link the guy had smoked weed for two years prior with no apparent issues. Yes his psychosis resolved after he stopped using cannabis, but he was also treated from that point onward with anti-psychotics (the kind you would treat schizophrenia with). It was probably the anti-psychotics, not the cannabis cessation that made him not psychotic.
I hear this argument every time someone does something bad on psychedelics and cannabis. I’ve also heard that, if the patient had no history of schizophrenia or related disorders, they must have just had it latent and were bound to get it anyway.
Bottom line is there is no way for any individual to really know if they have latent schizophrenia anyway, and I think it’s a conveniently non-disprovable explanation for why psychedelics and cannabis aren’t bad.
I think calling cannabis bad or good is a false dichotomy. Sometimes peanuts kill children, that doesn't make peanuts "bad". Maybe cannabis causes schizophrenia in rare cases, does that make it "bad"?
In this specific case, the authors started him on a treatment for schizophrenia and he got better. Why continue him on this treatment if they thought it was simply the cannabis that caused it (as he would abstain from then on). Also, they increased his dose prior to discharge.
I'm not arguing that cannabis didn't cause his schizophrenia, just that this doesn't sound like cannabis induced psychosis, which is a different diagnosis with different prognosis.
I've long had this sense, that if I started smoking weed every day, I probably would develop psychosis sooner or later. I feel like my connection to reality is at times somewhat tenuous, and heavy cannabis could easily disturb it enough to break it entirely. I suppose I could be wrong, but that's a hypothesis I'm not going to test.
I do think some people can have that "latent" potential yet have the good fortune of never activating it – and cannabis definitely has the potential to do so (although most recreational drugs probably can given sufficiently heavy long-term use).
(I tried cannabis once, years ago, I could see why people like it but I didn't feel any great urge to repeat the experience – and worries like this also discourage me – which is probably for the best.)
See this paper – Veeder TA, Leo RJ. Male genital self-mutilation: a systematic review of psychiatric disorders and psychosocial factors. Gen Hosp Psychiatry. 2017 Jan-Feb;44:43-50. https://doi.org/10.1016/j.genhosppsych.2016.09.003 Epub 2016 Sep 14. PMID: 28041576.
To quote its abstract:
> Data were obtained from 173 cases: genital mutilation (n=21), penile amputation (n=62), castration (n=56) and combined amputation/castration (n=34). Common psychiatric disorders included schizophrenia spectrum (49%), substance use (18.5%), personality (15.9%) and gender dysphoric disorders (15.3%)
So, while it is almost 50% schizophrenia spectrum, substance use is the second most common cause (although personality disorders and gender dysphoria are not far behind, and the difference between the three might not be statistically significant.)
Thanks, I searched for cannabis specifically which would explain why this didn't show up. I imagine much of the substance use auto amputations are in people who do things like PCP.
Good point, I edited it to add a note. I should have warned people but I forgot.
Also, my mother is a doctor, and when I was a teenager (even tweenager) I used to love to read her medical journals and textbooks–it has made me rather immune to the unsightly images they sometimes contain–although, interestingly, images which I can view nonchalantly in a medical context will still freak me out if divorced from that context.
I know some who don’t touch a drop of alcohol. Maybe some early 20 yos do but that lifestyle can’t be too productive, pot and alcohol amplify eachother’s effects and get you seriously intoxicated
Quite a bit of research is available on the effects of cannabis use — the problem is that people don't read it.