Marijuana linked to Psychosis?

There is growing evidence of a link between the use of marijuana and mental disease.

Marijuana use at a young age significantly increased the risk of psychosis in young adulthood, Australian investigators reported.

Young adults who reported a longer duration since first exposure to marijuana had a two- to fourfold greater prevalence of three different psychosis-related outcomes, John McGrath, MD, PhD, of the Queensland Center for Mental Health Research in Wacol, and colleagues concluded in an article published online in Archives of General Psychiatry.

Several prospective-cohort studies have demonstrated an association between early marijuana use and an increased risk of psychosis. On the basis of such studies, reviews of the issue have generally concluded that early use of marijuana, or cannabis, is a modifiable risk factor for psychosis-related outcomes, the authors wrote.​

http://www.medpagetoday.com/Psychiatry/Addictions/18722
More info from another article:

Several lines of evidence support the potential biologic plausibility of these links between cannabis use and psychosis. First, exogenous (eg, Δ-9-tetrahydrocannabinol) and endogenous cannabinoids (eg, anandamide) exert their effects (such as modulating the release of neurotransmitters including dopamine and glutamate) by interactions with specific cannabinoid (CB1) receptors that are distributed in brain regions implicated in schizophrenia. Second, several studies have shown an increased CB1 receptor density in brain regions of interest in schizophrenia, including the dorsolateral prefrontal cortex and the anterior cingulate cortex.[17,18] Third, other studies report elevated levels of endogenous cannabinoids in the blood and cerebrospinal fluid of patients with schizophrenia.[19-21] Fourth, acute, controlled administration of Δ-9-tetrahydrocannabinol causes both patients and controls to experience transient increases in cognitive impairments and schizophrenia-like positive and negative symptoms.[22] In summarizing these and many other findings, Fernandez-Espejo and colleagues[23] have suggested that the endocannabinoid system is altered in schizophrenia and that dysregulation of this system, perhaps induced by exogenous cannabis, can interact with neurotransmitter systems in a way so that a "cannabinoid hypothesis" can be integrated with other neurobiologic hypotheses (eg, those involving dopamine and glutamate).
Conclusion

In sum, a growing body of clinical and epidemiologic research suggests significant but complex links between cannabis use and psychosis. Concurrently, ongoing neurobiologic research is revealing findings in the endocannabinoid system that appear to support the biologic plausibility of such links. It should be noted that much of the research conducted to date does not allow for causal determinations. Ongoing research of varying designs will undoubtedly enlighten the field.​

http://www.medscape.com/viewarticle/719139

 

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There is a link, but no one is sure if it merely potentiates an existing condition or if it actually causes sane people to develop mental problems. In any case, even accounting for such factors, it is one of the safest drugs out there. No one has ever died from it, unlike alcohol or over the counter drugs.

 

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Didn't we have this same exact thread here like two weeks ago?

 

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I'm so wasted, I'm not sure.

 

Mad, there is one problem with these sorts of studies, that is that they dont test cause and effect properly. For instance other studies have found that your 10 times more likly to use drugs if you have an undiognosed mental illness and in the case of skizophrenia the drug of choice apears to be weed. So is the weed causing the psycotic break OR is the undiognosed skizophrenia which is being controled by the weed causing BOTH the psycotic break AND the weed use?

The only way to tell would be concidered unethical, ie to do a randomised controled trial on weed

 

Did you read this?

Several lines of evidence support the potential biologic plausibility of these links between cannabis use and psychosis. First, exogenous (eg, Δ-9-tetrahydrocannabinol) and endogenous cannabinoids (eg, anandamide) exert their effects (such as modulating the release of neurotransmitters including dopamine and glutamate) by interactions with specific cannabinoid (CB1) receptors that are distributed in brain regions implicated in schizophrenia. Second, several studies have shown an increased CB1 receptor density in brain regions of interest in schizophrenia, including the dorsolateral prefrontal cortex and the anterior cingulate cortex.[17,18] Third, other studies report elevated levels of endogenous cannabinoids in the blood and cerebrospinal fluid of patients with schizophrenia.[19-21] Fourth, acute, controlled administration of Δ-9-tetrahydrocannabinol causes both patients and controls to experience transient increases in cognitive impairments and schizophrenia-like positive and negative symptoms.[22] In summarizing these and many other findings, Fernandez-Espejo and colleagues[23] have suggested that the endocannabinoid system is altered in schizophrenia and that dysregulation of this system, perhaps induced by exogenous cannabis, can interact with neurotransmitter systems in a way so that a "cannabinoid hypothesis" can be integrated with other neurobiologic hypotheses (eg, those involving dopamine and glutamate).​

So there is a plausible mechanism for the link between psychosis and marijuana and the administration of Δ-9-tetrahydrocannabinol induces temporary schizo type symptoms.

 

“They” do, I can assure you. Scientists/doctors aren’t a bunch of simpletons who don’t know how to construct a valid experimental regimen. “They” are all very much aware of cause and effect. Always be aware of simplification and dumbing down of science by mainstream news reporting.

The dangers of cannabis exacerbating various psychological illnesses have been widely known and majority accepted in the medical and scientific community for a while now. New supporting evidence comes to light constantly from laboratory experiments and well-designed clinical analyses. It’s really only on internet science forums that Google-armed apologists try to argue that there’s no link.

 

Sciforums is stagnant.

 

And always be wary of assumptions regarding the people you are talking to. Just because i cant spell very well doesnt mean i dont know what im talking about. I dont get my info from the internet, i get it from books and lectures on mental health and drug adiction all of which show that though there is an association and a good working theory there isnt any provable causal link as of every piece of evidence avilable as of the publication date of Elder (et al) 'Psychiatric and mental health nursing' (cant give the date because MY copy is 2 versions older than the one we were using last year)

The studies have only ever been retrospective anayslis or theory based. Possably some animal studies but there havent been any longterm randomised controled trials i have herd of. Oh and the "they" wasnt a person, if you had read the preciding statment you would have seen that the 'they' was refering to longitudional and retrospective resurch which IS unreliable when it comes to cause and effect because the variables cant be controled. As i said the rate of canabis use is more than 10 times higher in people who have undiognosed skizophrenia (mainly as well as bipolar and some other mental health illnesses, not depression which is more closly linked to alchole and tobacco), so unless a study can PROVE conclusivly (not chemically or theoretically) that the mental illness follows rather than preciding the canibus use (not possable in a retrospective study) then we have no new infomation.

Rember that just because a substance CAN do something doesnt mean it DOES do something, digitalis can cause cardiac arest but its highly unlikly that all the cardiac arests from people taking digitalis are caused by it rather than by the cardiac condition the digitalis they are taking to TREAT it.

The same problem arises with antidepressants, sure they are linked with suicide because they give people so depressed that they have no motivation and energy to do anything there motivation and energy back and what do you find? early in the treatment people are more likly to comit suicide because they have the energy and motivation without the cure yet as its still building up (which is why all people on antidepressants should be monitored for sudden changes in the first few months).

Adrenilin is another drug used to stop a cardiac arest which can actually CAUSE a cardiac arest and so for that matter can electric shocks.

You cant relie on chemical studies, animal studies have limited value and retrospectives are almost usless for the most part. The only studies which can give conclusive evidence are those banned because of ethics concerns, large scale, randomised controled trials.

 

Temporary. Big deal. I call that getting high. :m:

 

I actually thought that the last (and recent) time this issue came up, most people focused on the fact that alcohol can lead to pretty much all of the problems marijuana can AND has a much more violent profile - iow leads to more problems for other people - rape, assault, chronic abuse, etc. To me it seemed that most people were not denying the potential effects of regular marijauna use, but rather putting those effects in context.

Of course research into the consequences of any drug are useful and neutral. But there tends to be an undercurrent political side to those who post negative findings about marijuana. It's not a coincidence that this time it is madanthonywayne and the last time, I believe, it was also a conservative poster. In general the right likes to notice and highlight the problems of marijuana because of the politics - partially only perceived - of the users - which really are connected to the effects of the drug. They tend not to want to notice that alcohol leads to many of the same problems and has much more brutal consequences for non-users in the lives and communities of alcohol users.

So it's not as if this is all a simply sharing of facts between, for example, two researchers.

While individual researchers may or may not be savvy to the complexities of cause and effect - and not all of them are, and those that are are to varying degrees - the way in which 'information' like this appeals in the public - like this thread - tends to be extremely misleading about cause and effect, especially in the context of drug use in general in society.

 

I didn't participate in the previous thread. I only became aware of the link between marijuana use and psychosis via a medline update I was recently reviewing.

On the other hand, I constantly hear people going on about how marijuana is perfectly safe.

I'm in favor of legalizing all drugs (including alcohol, which it sounds like you want to ban). People have the right to do what they want to their own bodies.

"Information", in quotes? There is nothing in the OP not supported by science and calling it misleading suggests to me that it is you that has a political agenda and wants to hide any evidence of the deleterious effects of marijuana use.

 

Are you saying the mentally ill are not safe? I call that discrimination.

The fact is, :m: contains both psychotic and anti-psychotic constituents. Recent breeding has resulted in strains that do not contain enough anti-psychotic constituents. That can be remedied through legalization and regulation. We can put labels on it outlining it's exact contents.

 

well, i don't know--from the Medical News article you posted this:

however, further along within the full article we find this:

for part of the study, they assessed three psychosis-related outcomes: nonaffective psychosis, hallucinations (assessed by the Computerized International Diagnostic Interview), and the Peters et al Delusions Inventory (PDI) score (Schizophr Bull 2004; 30: 1005-1022). but for the sibling pairs, , they used only the Peters et al Delusions Inventory, which is intended to measure schizotypal traits, or delusional ideation, in the general population (http://schizophreniabulletin.oxfordjournals.org/cgi/content/short/30/4/1005). schizotypal traits and delusional ideation are emphatically not the same as psychosis, though they can be said to be "psychosis related":

http://en.wikipedia.org/wiki/Schizotypy


note the bolded portion at the beginning of your citation:

sounds kinda misleading to me.

 

I'm not a psychiatrist and am unfamiliar with the various tests used to assess psychosis. However, I linked to more than one article and the articles referenced more than one study. So even if there was some error in assessing schizophrenic traits in one particular study, that does not invalidate every other study. And it certainly does not reflect any attempt to mislead on my part - which is what Doreen seemed to be implying.

 

i wasn't so much implying that you were intending to mislead (and i don't suspect that Doreen was either), but rather that the article itself is misleading. and as to the matters of others studies, the second suggests "significant but complex links between cannabis use and psychosis," which is hardly the same as the claim made at the beginning of the first article: "Marijuana use at a young age significantly increased the risk of psychosis in young adulthood." this latter claim does not seem to be supported within the article itself.

i cannot find the actual peters et al delusions inventory in anything but a pdf, so i cannot quote from it and i don't feel inclined to type out the questions--but here is a link: http://schizophreniabulletin.oxfordjournals.org/cgi/reprint/30/4/1005.pdf. the 21 questions are towards the end of the document. if you review the questions you will see how answering such honestly could be very difficult for anyone who is attentive to language; IOW, in my lay opinion, the responses of an educated person could not yield meaningful results--that is, meaningful to one who is trying to assess religiosity, grandiosity, and related attributes.


edit: and as noted above, the PDI does not purport to assess for traits of schizophrenia, but rather for schizotypy.

 

i'm not entirely clear as to how what you are saying here relates to what is being posited in the first article cited--posited by the writer of the article, that is; the researchers do not state in their conclusions anything like what the writer of the article claims in the first sentence--namely, that "marijuana use at a young age significantly increased the risk of psychosis in young adulthood." this is the matter of contention.

[the conclusions of the researchers were as follows: "Early cannabis use is associated with psychosis-related outcomes in young adults. The use of sibling pairs reduces the likelihood that unmeasured confounding explains these findings. This study provides further support for the hypothesis that early cannabis use is a risk-modifying factor for psychosis-related outcomes in young adults." http://archpsyc.ama-assn.org/cgi/content/full/2010.6 ]

this--the claim of the writer of the article, not the claims of the researchers--is hardly the same as stating that marijuana can exacerbate an existing, and possibly latent, condition. not only do the media simplify and dumb-down the findings, they grossly distort and misstate them.

 

The science aside, it's a small price to pay for ending the far larger tragedies going on daily as the result of prohibition.

 

Here I agree. I am totally opposed to prohibition. It's idiotic, unjust, and a waste of precious resources.

 

And I don't know anyone in the movement that says it's totally benign, with no side effects whatsoever.