6 ms·

Marijuana use and schizophrenia: New evidence suggests link

41 points by Mz 10y ago

_98fj 10y ago
Isn't it established since about 25 years that any drug-use can bring onset of schizophrenia in those vulnerable?
- saalaa 10y ago
  In fact it's highly debated by psychiatrists and social workers. They argue that Marijuana consumption forces many to maintain some form of social links which, were it not for Marijuana, they very likely wouldn't (I'm specifically talking about schizophrenia cases here).
  - andai 10y ago
    More info? That sounds fascinating. Mini anecdote: met a very friendly schizophrenic guy in a coffeeshop who got really paranoid and uncomfortable after he smoked... and apparently he smoked all the time.
  - reflexive 10y ago
    Marijuana consumption forces many to maintain some form of social links Ironically, that's only true when marijuana is illegal, hence a poor argument for legalization. Legal substances may be easily purchased with minimal social interaction.
- DanBC 10y ago
  The correlation between drug use and schizophrenia is very clear. There's considerable debate about the causality. Does psychosis cause people to smoke more cannabis? (It causes people to smoke more cigarettes). Does cannabis cause people who would not have had psychosis otherwise to get it? Or does cannabis just bring out an underlying psychosis that the person probably would have experienced anyway? It's probably a bit complicated, with circular stuff going on. While I'm strongly in favour of legalisation of all drugs I am a bit worried when some of the legalise crowd refuse to accept that there might be health risks. (I'm also frustrated when the anti crowd refuse to accept that the situation is probably a bit more complicated than "drugs make you mad")
  - kolinko 10y ago
    Speaking of smoking cigarettes - there is an excellent paper outlining all the neuropsychiatric diseases where smoking may be actually a method of a self-medication. https://pdfs.semanticscholar.org/f961/639e2a998d275f3e8f8f4ccb41564a00d63f.pdf https://pdfs.semanticscholar.org/f961/639e2a998d275f3e8f8f4c...
  - kahnpro 10y ago
    Or is it that people who have schizophrenia often belong to social classes that are more likely to use drugs? If poor people are more likely to use drugs, and poor people also have a higher incidence of schizophrenia, you could arrive at this correlation even if marijuana and psychosis are entirely unrelated.
    - mistersquid 10y ago
      Marijuana use actually may be more strongly correlated to higher socioeconomic status than lower. A quick Google search for "drug use by socioeconomic status" turns up a 2012 article titled "Socioeconomic Status and Substance Use Among Young Adults: A Comparison Across Constructs and Drugs" [0] which concludes, in part > Findings based on three indicators of family background > SES—income, wealth, and parental education—converged in > describing unique patterns for smoking and for alcohol and > marijuana use among young adults, although functional > relationships across SES measures varied. Young adults with > the highest family background SES were most prone to alcohol > and marijuana use. [0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3410945/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3410945/ EDIT: Change lede.
    - Broken_Hippo 10y ago
      Poor folks aren't more likely to use drugs: It seems that drug abuse is actually pretty common through society, but with poor folks using the least - mostly because drugs cost money. Poor people are more likely to get caught for using drugs, however, simply because of living spaces. You and a couple friends wanna get high? Low income, you might be in a car, on the corner, or in an alley. Higher income, you might be in your basement or pretty private backyard.
  - 10y ago
jessica00 10y ago
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jack9 10y ago
Looks a lot like propaganda. Not saying it's inaccurate, but pointed squarely.
- andai 10y ago
  Well.. if you have a latent mental illness and you take psychoactive substances, you may have a bad time. The issue is complicated: people often don't know about their illness and don't know that they respond differently to substances than other people do. I'm looking forward to a future where genetic testing for these things is as common as testing your drugs for purity (which, i hope, will also be be more common!)
  - jack9 10y ago
    > you take psychoactive substance So are they going to release individual studies for each of the other substances? This is the crux of the issue for me.
    - Broken_Hippo 10y ago
      Hopefully we'll get to that point. It isn't like the research is complete in any way.
- Broken_Hippo 10y ago
  Not everything is propaganda. This is more of a risk-knowledge sort of thing, and hopefully with legalisation we can know more about the actual risks involved and be able to self-screen so that we can know our personal risks. Look, if you know when you are newly 21 and finally legal to smoke that if you have a latent mental illness, smoking could make it rear its head, what do you do? For most of us, the risk is pretty small, so we go ahead. This is especially the case if we know what to do if things go south. But if your father was schizophrenic, you might think twice. If your older brother was as well, you might very well skip - or you might not care, deciding to not let worse case scenarios run your life. Sidenote: I think it is grand to have a complete view of these things - like most things, not all good but not all bad.
sageikosa 10y ago
tl;dr; those prone to schizophrenia may increase psychosis risk if they are consumers of marijuana.
- DanBC 10y ago
  The article links to the study (this is great, and I wish more people did that). The study has a nice tl;dr https://www.cambridge.org/core/services/aop-cambridge-core/content/view/122D651C3670683DAEDDA33997417105/S0033291716003172a.pdf/div-class-title-assessing-causality-in-associations-between-cannabis-use-and-schizophrenia-risk-a-two-sample-mendelian-randomization-study-div.pdf https://www.cambridge.org/core/services/aop-cambridge-core/c... > Results. There was some evidence consistent with a causal effect of cannabis initiation on risk of schizophrenia [odds ratio (OR) 1.04 per doubling odds of cannabis initiation, 95% confidence interval (CI) 1.01 1.07, p = 0.019]. There was strong evidence consistent with a causal effect of schizophrenia risk on likelihood of cannabis initiation (OR 1.10 per doubling of the odds of schizophrenia, 95% CI 1.05–1.14, p = 2.64 × 10−5). Findings were as predicted for the negative control (height: OR 1.00, 95% CI 0.99–1.01, p = 0.90) but weaker than predicted for the positive control (years in education: OR 0.99, 95% CI 0.97–1.00, p = 0.066) analyses. > Conclusions. Our results provide some that cannabis initiation increases the risk of schizophrenia, although the size of the causal estimate is small. We find stronger evidence that schizophrenia risk predicts cannabis initiation, possibly as genetic instruments for schizophrenia are stronger than for cannabis initiation
andai 10y ago
My friend in med school mentioned a study that found a number of genes for which smoking cannabis increases risk of developing schizophrenia, and a small number for which smoking cannabis actually decreases it! If anyone has heard of this I'd love a link to the study
sreeni_ananth 10y ago
https://www.ncbi.nlm.nih.gov/pubmed/8689377 https://www.ncbi.nlm.nih.gov/pubmed/8689377 seems to suggest increased paranoia with alcohol consumption as well. Probably makes the condition worse rather than being the root cause.
caub 10y ago
smoking never had a single positive effect
- m1sta_ 10y ago
  We'll see this comment referenced in the next issue of Nature.
- b6 10y ago
  https://www.youtube.com/watch?v=pInkduXOQac https://www.youtube.com/watch?v=pInkduXOQac
  - andai 10y ago
    Wow, thanks for sharing that
  - caub 10y ago
    that's bullshit, if the guy could just do some minimal sport and have a healthy life it would go much better
- caub 10y ago
  Oh, many smokers on HN
- deleted 10y ago
  [deleted]
reflexive 10y ago
Anecdotal evidence: Kurt Vonnegut's son Mark wrote a fascinating book ("The Eden Express", 1975) about his experience being schizophrenic and a prolonged psychotic episode triggered by marijuana consumption: https://en.wikipedia.org/wiki/The_Eden_Express https://en.wikipedia.org/wiki/The_Eden_Express
oblib 10y ago
I've seen these studies for years now and they always conclude the same thing but twist the headline and omit very important data in their study. They conclude: "There is growing consensus that cannabis use might increase the risk of developing schizophrenia. Our results support this, but also suggest that those at increased risk of schizophrenia may be more likely to try cannabis in the first place." I've never found any good reason to suspect a link between use and cause in their data and the link between schizophrenia and use is almost always consistent with use of other drugs as well, and most any drug as far as that goes. For example, almost all of those who used marijuana also used alcohol and prescriptions drugs as well, but links to those (and combinations of them) are completely or mostly ignored in these studies. Furthermore, they almost always suggest that "Paranoia" is one of the symptoms that Marijuana causes but they never address the fact that everyone they study has grown up with a lifetime of harsh disinformation and the very real threat of imprisonment for taking just a puff off a joint, which is a very good reason to get paranoid if you do. As they say "Just because I'm paranoid doesn't mean they're not out to get me." and in this case "They" most certainly have been and still are in most places and everyone has seen it happen. The real result of that is, if you're not paranoid you're a idiot and most schizophrenics are not idiots. Some of them are geniuses. (https://www.psychologytoday.com/blog/beautiful-minds/200903/schizophrenic-thought-madness-or-potential-genius https://www.psychologytoday.com/blog/beautiful-minds/200903/...)
- DanBC 10y ago
  > Furthermore, they almost always suggest that "Paranoia" is one of the symptoms that Marijuana causes but they never address the fact that everyone they study has grown up with a lifetime of harsh disinformation and the very real threat of imprisonment for taking just a puff off a joint, which is a very good reason to get paranoid if you do. This is a british study. http://www.rcpsych.ac.uk/healthadvice/problemsdisorders/cannabis.aspx http://www.rcpsych.ac.uk/healthadvice/problemsdisorders/cann... > A young person found to be in possession of cannabis will be: > Arrested > Taken to a police station > Given a reprimand, final warning or charge, depending on the offence. > After one reprimand, a further offence will lead to a final warning or charge. > After a final warning: > The young person must be referred to a Youth Offending Team to arrange a rehabilitation programme. > A further offence will lead to a criminal charge. That's pretty far from being imprisoned for a single puff.
sigstoat 10y ago
as i understand it, the growing opinion of toxicologists (who, if drug use comes up in court, are the ones who get to have expert opinions on what drugs do), is that the delta-9-THC can cause short term psychosis. on the other hand, CBD prevents it (and has most of the non-recreational benefits of the plant). further, THC and CBD levels can vary dramatically by strain. in this study, they do claim to measure THC concentration, but don't measure or talk about CBD, and have a sample size of 17. there's stuff going on that needs to be studied, but this study isn't contributing anything useful.

41 points by Mz 10y ago

_98fj 10y ago

Isn't it established since about 25 years that any drug-use can bring onset of schizophrenia in those vulnerable?

saalaa 10y ago
In fact it's highly debated by psychiatrists and social workers. They argue that Marijuana consumption forces many to maintain some form of social links which, were it not for Marijuana, they very likely wouldn't (I'm specifically talking about schizophrenia cases here).
- andai 10y ago
  More info? That sounds fascinating. Mini anecdote: met a very friendly schizophrenic guy in a coffeeshop who got really paranoid and uncomfortable after he smoked... and apparently he smoked all the time.
- reflexive 10y ago
  Marijuana consumption forces many to maintain some form of social links Ironically, that's only true when marijuana is illegal, hence a poor argument for legalization. Legal substances may be easily purchased with minimal social interaction.
DanBC 10y ago
The correlation between drug use and schizophrenia is very clear. There's considerable debate about the causality. Does psychosis cause people to smoke more cannabis? (It causes people to smoke more cigarettes). Does cannabis cause people who would not have had psychosis otherwise to get it? Or does cannabis just bring out an underlying psychosis that the person probably would have experienced anyway? It's probably a bit complicated, with circular stuff going on. While I'm strongly in favour of legalisation of all drugs I am a bit worried when some of the legalise crowd refuse to accept that there might be health risks. (I'm also frustrated when the anti crowd refuse to accept that the situation is probably a bit more complicated than "drugs make you mad")
- kolinko 10y ago
  Speaking of smoking cigarettes - there is an excellent paper outlining all the neuropsychiatric diseases where smoking may be actually a method of a self-medication. https://pdfs.semanticscholar.org/f961/639e2a998d275f3e8f8f4ccb41564a00d63f.pdf https://pdfs.semanticscholar.org/f961/639e2a998d275f3e8f8f4c...
- kahnpro 10y ago
  Or is it that people who have schizophrenia often belong to social classes that are more likely to use drugs? If poor people are more likely to use drugs, and poor people also have a higher incidence of schizophrenia, you could arrive at this correlation even if marijuana and psychosis are entirely unrelated.
  - mistersquid 10y ago
    Marijuana use actually may be more strongly correlated to higher socioeconomic status than lower. A quick Google search for "drug use by socioeconomic status" turns up a 2012 article titled "Socioeconomic Status and Substance Use Among Young Adults: A Comparison Across Constructs and Drugs" [0] which concludes, in part > Findings based on three indicators of family background > SES—income, wealth, and parental education—converged in > describing unique patterns for smoking and for alcohol and > marijuana use among young adults, although functional > relationships across SES measures varied. Young adults with > the highest family background SES were most prone to alcohol > and marijuana use. [0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3410945/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3410945/ EDIT: Change lede.
  - Broken_Hippo 10y ago
    Poor folks aren't more likely to use drugs: It seems that drug abuse is actually pretty common through society, but with poor folks using the least - mostly because drugs cost money. Poor people are more likely to get caught for using drugs, however, simply because of living spaces. You and a couple friends wanna get high? Low income, you might be in a car, on the corner, or in an alley. Higher income, you might be in your basement or pretty private backyard.
- 10y ago

jessica00 10y ago

Thank you for sharing the information here. Its much informative and really i got some valid information. You had posted the amazing article.site web <a href="http://www.design3i.com/school-website-design-uk/">School http://www.design3i.com/school-website-design-uk/">School website design uk</a>

jack9 10y ago

Looks a lot like propaganda. Not saying it's inaccurate, but pointed squarely.

andai 10y ago
Well.. if you have a latent mental illness and you take psychoactive substances, you may have a bad time. The issue is complicated: people often don't know about their illness and don't know that they respond differently to substances than other people do. I'm looking forward to a future where genetic testing for these things is as common as testing your drugs for purity (which, i hope, will also be be more common!)
- jack9 10y ago
  > you take psychoactive substance So are they going to release individual studies for each of the other substances? This is the crux of the issue for me.
  - Broken_Hippo 10y ago
    Hopefully we'll get to that point. It isn't like the research is complete in any way.
Broken_Hippo 10y ago
Not everything is propaganda. This is more of a risk-knowledge sort of thing, and hopefully with legalisation we can know more about the actual risks involved and be able to self-screen so that we can know our personal risks. Look, if you know when you are newly 21 and finally legal to smoke that if you have a latent mental illness, smoking could make it rear its head, what do you do? For most of us, the risk is pretty small, so we go ahead. This is especially the case if we know what to do if things go south. But if your father was schizophrenic, you might think twice. If your older brother was as well, you might very well skip - or you might not care, deciding to not let worse case scenarios run your life. Sidenote: I think it is grand to have a complete view of these things - like most things, not all good but not all bad.

sageikosa 10y ago

tl;dr; those prone to schizophrenia may increase psychosis risk if they are consumers of marijuana.

DanBC 10y ago
The article links to the study (this is great, and I wish more people did that). The study has a nice tl;dr https://www.cambridge.org/core/services/aop-cambridge-core/content/view/122D651C3670683DAEDDA33997417105/S0033291716003172a.pdf/div-class-title-assessing-causality-in-associations-between-cannabis-use-and-schizophrenia-risk-a-two-sample-mendelian-randomization-study-div.pdf https://www.cambridge.org/core/services/aop-cambridge-core/c... > Results. There was some evidence consistent with a causal effect of cannabis initiation on risk of schizophrenia [odds ratio (OR) 1.04 per doubling odds of cannabis initiation, 95% confidence interval (CI) 1.01 1.07, p = 0.019]. There was strong evidence consistent with a causal effect of schizophrenia risk on likelihood of cannabis initiation (OR 1.10 per doubling of the odds of schizophrenia, 95% CI 1.05–1.14, p = 2.64 × 10−5). Findings were as predicted for the negative control (height: OR 1.00, 95% CI 0.99–1.01, p = 0.90) but weaker than predicted for the positive control (years in education: OR 0.99, 95% CI 0.97–1.00, p = 0.066) analyses. > Conclusions. Our results provide some that cannabis initiation increases the risk of schizophrenia, although the size of the causal estimate is small. We find stronger evidence that schizophrenia risk predicts cannabis initiation, possibly as genetic instruments for schizophrenia are stronger than for cannabis initiation

andai 10y ago

My friend in med school mentioned a study that found a number of genes for which smoking cannabis increases risk of developing schizophrenia, and a small number for which smoking cannabis actually decreases it! If anyone has heard of this I'd love a link to the study

sreeni_ananth 10y ago

https://www.ncbi.nlm.nih.gov/pubmed/8689377 https://www.ncbi.nlm.nih.gov/pubmed/8689377 seems to suggest increased paranoia with alcohol consumption as well. Probably makes the condition worse rather than being the root cause.

caub 10y ago

smoking never had a single positive effect

m1sta_ 10y ago
We'll see this comment referenced in the next issue of Nature.
b6 10y ago
https://www.youtube.com/watch?v=pInkduXOQac https://www.youtube.com/watch?v=pInkduXOQac
- andai 10y ago
  Wow, thanks for sharing that
- caub 10y ago
  that's bullshit, if the guy could just do some minimal sport and have a healthy life it would go much better
caub 10y ago
Oh, many smokers on HN
deleted 10y ago
[deleted]

reflexive 10y ago

Anecdotal evidence: Kurt Vonnegut's son Mark wrote a fascinating book ("The Eden Express", 1975) about his experience being schizophrenic and a prolonged psychotic episode triggered by marijuana consumption: https://en.wikipedia.org/wiki/The_Eden_Express https://en.wikipedia.org/wiki/The_Eden_Express

oblib 10y ago

I've seen these studies for years now and they always conclude the same thing but twist the headline and omit very important data in their study. They conclude: "There is growing consensus that cannabis use might increase the risk of developing schizophrenia. Our results support this, but also suggest that those at increased risk of schizophrenia may be more likely to try cannabis in the first place." I've never found any good reason to suspect a link between use and cause in their data and the link between schizophrenia and use is almost always consistent with use of other drugs as well, and most any drug as far as that goes. For example, almost all of those who used marijuana also used alcohol and prescriptions drugs as well, but links to those (and combinations of them) are completely or mostly ignored in these studies. Furthermore, they almost always suggest that "Paranoia" is one of the symptoms that Marijuana causes but they never address the fact that everyone they study has grown up with a lifetime of harsh disinformation and the very real threat of imprisonment for taking just a puff off a joint, which is a very good reason to get paranoid if you do. As they say "Just because I'm paranoid doesn't mean they're not out to get me." and in this case "They" most certainly have been and still are in most places and everyone has seen it happen. The real result of that is, if you're not paranoid you're a idiot and most schizophrenics are not idiots. Some of them are geniuses. (https://www.psychologytoday.com/blog/beautiful-minds/200903/schizophrenic-thought-madness-or-potential-genius https://www.psychologytoday.com/blog/beautiful-minds/200903/...)

DanBC 10y ago
> Furthermore, they almost always suggest that "Paranoia" is one of the symptoms that Marijuana causes but they never address the fact that everyone they study has grown up with a lifetime of harsh disinformation and the very real threat of imprisonment for taking just a puff off a joint, which is a very good reason to get paranoid if you do. This is a british study. http://www.rcpsych.ac.uk/healthadvice/problemsdisorders/cannabis.aspx http://www.rcpsych.ac.uk/healthadvice/problemsdisorders/cann... > A young person found to be in possession of cannabis will be: > Arrested > Taken to a police station > Given a reprimand, final warning or charge, depending on the offence. > After one reprimand, a further offence will lead to a final warning or charge. > After a final warning: > The young person must be referred to a Youth Offending Team to arrange a rehabilitation programme. > A further offence will lead to a criminal charge. That's pretty far from being imprisoned for a single puff.

sigstoat 10y ago

as i understand it, the growing opinion of toxicologists (who, if drug use comes up in court, are the ones who get to have expert opinions on what drugs do), is that the delta-9-THC can cause short term psychosis. on the other hand, CBD prevents it (and has most of the non-recreational benefits of the plant). further, THC and CBD levels can vary dramatically by strain. in this study, they do claim to measure THC concentration, but don't measure or talk about CBD, and have a sample size of 17. there's stuff going on that needs to be studied, but this study isn't contributing anything useful.