March 01, 2005

Marijuana Doubles Risk of Schizophrenia

The BBC News reported today on a new research study out of New Zealand that highlights the greatly increased risk of mental illness associated with Marijuana use.

"Smoking cannabis virtually doubles the risk of developing mental illnesses such as schizophrenia, researchers say. The New Zealand scientists said their study suggested this was probably due to chemical changes in the brain which resulted from smoking the drug.

The study, published in the journal Addiction, followed over 1,000 people born in 1977 for 25 years."

The researchers stated that "The weight of the evidence clearly suggests that the use of cannabis may alter underlying brain chemistry and precipitate the onset of psychosis [and therefore schizophrenia]... in vulnerable individuals," the University of Otago scientists reported in the journal, Addiction.

In another news report on this research study, AAP in Brisbane wrote that in an interview the researchers stated " "The critical thing is that many researchers feel now that if people (with schizophrenia) had not smoked marijuana they would not have gone on to develop schizophrenia and that's a really important public health message.

"It's a sufficient trigger in those individuals to tip them over. (But) we actually can't tell who those vulnerable individuals are."

For the Full story go to:

BBC News - Drug 'doubles mental health risk'

For the original Research go to:

Tests of causal linkages between cannabis use and psychotic symptoms

More Information:

How marijuana (cannabis) increases risk of schizophrenia


This article and the other articles on the relationship of THC and schizophrenia is interesting, but like all the others, not quite convincing.

First, there is too much commingling of THC with �street drugs� (other articles), and no clear indication why cannabis is singled out and the others disregarded.

The acknowledged commingling of drugs (e.g., alcohol, cocaine, heroin, nicotine and perhaps caffeine, ecstasy and amphetamines) with THC, and then concluding that THC is the culprit is disturbing. It calls into question the integrity of the whole body of research on this web site about schizophrenia and mental illness and its causes. Credibility is greatly compromised.

I�ve been unable to find any articles relating schizophrenia and mental illness in general to tobacco products. Yet people suffering from these brain disorders seem to be heavily addicted to tobacco products. It�s my understanding that tobacco (perhaps nicotine) does alter the brain�s dopamine production system.

There were several articles suggesting that Essential Fatty Acids (EFAs) may be beneficial in preventing the onset of these brain disorders.

The hemp plant contains these EFAs (including GLA) in just about the ideal proportion the body needs.

In all the studies I�ve read, I don�t see any that address the issue that the use of THC may be in response to the body�s cannabinoid receptors signaling a craving for these EFAs. THC may be the only available part of the hemp plant that these people are able to obtain that would satisfy that craving without actually supplying those nutrients.

Historically, the whole hemp plant was used for food, medicine and recreationally, often in an experiential religious context. What seems to be called �psychosis� may be a form of �psychic phenomena� or �spiritual events.�

Lastly, the graphics showing schizophrenia as a disease spreading through the brain seems a bit farfetched to ascribe that to THC. This disease-spreading phenomenon seems a far more likely explanation of the symptoms more commonly associated with schizophrenia.

I find the articles attempting to link schizophrenia and other mental illnesses to THC lacking. I find the word �suggest� used all too often. Cause seems to be an elusive fairy. I think you�re barking up the wrong tree.

The various research articles at this web site trying to link a disease spreading throughout the brain to THC is at best interesting, but unreliable.

Posted by: David Dunn at May 15, 2005 05:30 AM

The study is ridiculous. I first developed schizophrenia in 1975 at the age of 24. After terrible experience with the DISEASE, which is what it is, they hit on giving me prolixin which proved to be very effective on me. When I could have had disability handed to me on a silver platter long ago, I have chosen to work and still do. I could go into great detail about my subjective and objective observations about the disease, and will do so on another board somewhere on this site as I have taken a recent interest in the site in order to share my personal experience with the disease and my own objective and subjective experience with it.
But the simple point to make in refuting this absurd study is that if cannabis use really made more people schizophrenic then it would show up in the per capita statistics which it does not. Schizophrenics continue to make up a steady one per cent of the population. This is clear indication that the disease is genetic in nature.

Posted by: Bobby Seay at June 26, 2005 11:18 AM

It is interesting to note that in our city the NA And AA groups have recently added Schizophrenics Anonymous as an aditional meeting ground.
The relation between drugs/ alcohol and psychosis is visible and obvious.
As regards what came first addiction or psychiatric disorder is what shall always remain a mystry.

Posted by: monica at July 18, 2005 09:30 PM

WOW!!! That was so interesting!

Posted by: nana at July 19, 2005 09:08 AM

THC does increase the risk of schizophrenia. A friend of mine became psychotic when increasing thc doses, and the same happened to me. How strong the dosage is is the strictly important issue. I don't think I were "fragile", it's just that if you smoke 6/7 enormous bongs a day by yourself, things go crazy. You just notice it.


Posted by: lorenzo at September 28, 2005 08:31 PM

I haven't looked at this site since my last post. My mother has died. To the statement that pot causes psychosis made above, about smoking bongs and bongs a day. Yeah, I suppose you could stay fried forever and get nothing done all day just as you could stay drunk forever, like many do as that is the biggest drug problem in
America, and get nothing done either and get real psychotic. Psychosis, after all, is described as disassociation from reality. An ounce of pot smoked a day will do that. I don't, and most don't, smoke that much.
I take my prolixin pills every day now, and haven't had a psychotic episode in the seven years since a good psychiatrist of mine put me on them instead of the heavy duty booster shots every two weeks. And I still smoke my pot after work and so forth. And I will say again I haven't had a psychotic episode in years and years.
Make what you will of the facts of the matter as I state above. But in the end this attempt to link pot with psychosis is ridiculous. The arguments made for the link are not logical. This ole pot smoker beats chess computers for fun. My brain is not fried one bit. I am a totally functional schizophrenic. One of the fortunate that anti-psychotics are very effective on. In spite of being a pot head for over 30 years.
Maybe one fine day the rabid right wing will figure out that justice and truth matter more than bull crap science to justify thier rabid right wing bankrupt agenda, but I doubt it. Global warming and environmental disaster will put an end to their stupidity about the environment, pot, and every other issue to an end soon enough.
Gilthoron the Stareagle
aka Bobby Seay

Posted by: Bobby Seay at August 30, 2006 04:31 PM

hi im 15 and have smoked pot, ciggarrettes and drank alcohal since i was 13. i am skitzophrenic since 5 months ago when i had my psychotic episode but i am now recovered and still taking my invega. so i am adopted and about 8 or 9 months ago (while i was still useing marijuana) my mom and dad tell me that my birth mom was skitzophrenic for the same reason i am and she doesnt beleave she gave birth to me because she lives in a nother world. since my recovery i am fully functional as the way i used to be and have smoked a couple times and havent had any problems since and yet still debating if i should smoke just everyonce in awhile. I have drank many times and have no problems with that. Many people say it would be okay to smoke every once in awhile but other dont agree. i would still like more answers???

Posted by: blake holland at November 7, 2007 05:18 PM

Viewing medical records of patients discharged from a psychiatric hospital last week, most of the 26 cases had a diagnosis of schizophrenia. 90% of the schizophrenia cases had marijuana use or abuse documented in their history. The odd thing was that most of these patients were under the age of 30 years old. Something to think about....Though many do not want to admit it....there is a direct correlation between psychotic disorders and marijuana and other drug use. The chemical make-up of the brain is very delicate. I believe these brain chemical altering drugs can directly and permanently impact brain function. Additionally, I believe that every young person should be educated regarding this potential danger to their future wellbeing, instead of waiting for some researcher or government organization to accept what has been proven true time and time again by reality. I can look at records of patients wih psychotic disorders any given day and see the same results. How much proof do we need????

Posted by: Rachel at December 9, 2007 05:30 PM

I think marijuna can cause schizophrenia if it is smoked everyday for 7years because that is how it was with me i smoked all the time and even sold it so I was thinking it was a free high and nothing happens but the poency is not the same as the 60's i know use cocaine and have quit smoking as much but taking medicine has lessen my episodes but i still cant deal with life with out some time of stimulant why i think it should be legalized for mental patients

Posted by: shawn at June 7, 2008 09:06 PM

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