Cannabis And Smoking Gene Links To Schizophrenia â??unfoundedâ??

[water]

16 November 2007

MedWire News: Schizophrenia risk is not influenced by variations in the cannabinoid receptor (CNR1) and alpha7-nicotinic acetylcholine receptor (CHRNA7) genes, say UK researchers.

They also found no evidence for the purported effects of cannabis use on schizophrenia according to variation in the catechol-O-methyltransferase (COMT) gene.

Schizophrenia is associated with an increased use of tobacco and cannabis, with evidence suggesting that patients may use the drug to alleviate neurophysiological symptoms. The benefits of these substances are thought to be mediated through their effects on CHRNA7 and CNR1, respectively, notes the team.

They therefore looked at the effects of variants in the genes encoding CHRNA7 and CNR1 on the risk for schizophrenia and the potential effects of tobacco and cannabis use.

Stanley Zammit, from Cardiff University, and colleagues genotyped 750 patients with schizophrenia and 688 mentally healthy controls for the CHRNA7 promoter polymorphism -86C/T and the CNR1 polymorphism rs1049353. They also gathered information on tobacco and cannabis use via interviews and case-note records.

In addition, the team conducted a case-only study of 493 participants from the schizophrenia group, examining interactions between cannabis use and the Val158Met polymorphism in the COMT gene, as well as the rs737865 and rs165599 single nucleotide polymorphisms (SNPs).

The team reports in the British Journal of Psychiatry that there was no evidence of an association between the CHRNA7 -86C/T genotype and schizophrenia. Schizophrenia patients were 4.4 times more likely than controls to smoke, but among the schizophrenia patients, there was no association between tobacco use and the -86C/T genotype.

Similarly, there was no significant association between the CNR1 rs1049353 genotype and schizophrenia. Schizophrenia patients were 2.6 times more likely than controls to use cannabis, but cannabis use was not affected by rs1049353 genotype among schizophrenia patients.

The results also showed that there were no associations between the Val158Met genotype and cannabis use, or between cannabis use and the variations at rs737865 and rs165599.

The only genetic effect on phenotypes of schizophrenia was a weak association between the -86C/T genotype and a younger age at onset of schizophrenia.

â??In summary, we failed to find any evidence that variation at the CHRNA7 or CNR1 locus was associated with schizophrenia, or that the effect of variation at these loci was modified by use of tobacco or cannabis, respectively,â?� the researchers write.

They add: â??Cannabis use was not associated with the presence of valine allele at Val158Met with COMT in our sample, therefore our findings do not support a previous report of a putative geneâ??environment interaction between COMT genotype and cannabis use on risk of schizophrenia.â?�


read this on another site i use and thought it should be shared

water Reviewed by water on 11-18-2007. Cannabis And Smoking Gene Links To Schizophrenia â??unfoundedâ?? 16 November 2007 MedWire News: Schizophrenia risk is not influenced by variations in the cannabinoid receptor (CNR1) and alpha7-nicotinic acetylcholine receptor (CHRNA7) genes, say UK researchers. They also found no evidence for the purported effects of cannabis use on schizophrenia according to variation in the catechol-O-methyltransferase (COMT) gene. Schizophrenia is associated with an increased use of tobacco and cannabis, with evidence suggesting that patients may use the drug to Rating: 5

[Dream of the iris]

So basically, Cannabis doesn't induce schizophrenia?

[Storm Crow]

Yep!

Symptoms of schizotypy precede cannabis use.
UKCIA forum :: Research :: Symptoms of schizotypy precede cannabis use.

Cannabidiol as an antipsychotic
Clinical Studies and Case Reports

Cannabis does not induce schizophrenia,
Cannabis does not induce schizophrenia, Dutch scientists say

Cannabis use does not cause schizophrenia
Cannabis use does not cause schizophrenia

Cannabinoids and psychosis.
Cannabinoids and psychosis. [Int Rev Neurobiol. 2007] - PubMed Result

Cannabis as a psychotropic medication
Cannabis as a psychotropic medication -- Chaturvedi 185 (1): 78 -- The British Journal of Psychiatry

Study Shows Long Term Marijuana Users Healthy
Erowid Cannabis Vault : Health Effects : Study #3

Cannabis and schizophrenia link blurs further
Cannabis and schizophrenia link blurs further - health - 16 April 2005 - New Scientist

Evidence does not show a strong causal relation between the use of cannabis and psychosocial harm
NLH - Mental Health - Aetiology - Review: current evidence does not show a strong causal relation between the use of cannabis in young people and psychosocial harm

No Increased Schizophrenia Risk With Use Of Cannabis
No Increased Schizophrenia Risk With Use Of Cannabis: The Hempire - [cannabis, london]

[the image reaper]

thanks for this post ... it will probably be the only place it will be seen ... while the first report of damning 'evidence' was plastered everywhere you looked for a week, this discrediting will probably go un-noticed by the general public ... :smokin:

[Dream of the iris]

Whew! I was so terrified I'd go crazy from smoking that I stopped. Thanks for this!

[Storm Crow]

So, make a copy or ten and leave them at the college library or lounge, at the laundromat, at the bus stop. If the "free" press won't do it, the WE have to! Our government was formed by folks taking matters in their own hand- are we wimpier than they were? Or do you like the way things are now???? You can afford to print up a few pages! - Granny:hippy:

[Dream of the iris]

It still doesn't explain those who get schizophrenia so clearly after smoking weed, though. I mean, they didn't "have schizophrenia" to begin with, so what about those people? What is this "genetic vulnerability"?

[sarah louise]

It still doesn't explain those who get schizophrenia so clearly after smoking weed, though. I mean, they didn't "have schizophrenia" to begin with, so what about those people? What is this "genetic vulnerability"?

That's not what the study is about. The study shows that people diagnosed with schizophrenia (sz) do not have a gene variation that causes them to smoke more tobacco or cannabis than the average Joe.

Many people experiment with weed in their teens and the prime onset time for schizophrenic symptoms is late adolescence to early adulthood. This may prove to be the only link between weed use and onset of sz. You might as well ask about the people who drank Coke before lapsing into sz.

If you ask many people who smoke and are diagnosed with sz they will say the same things as other people who smoke.
I like it, it helps me through the day, it relaxes me, I don't get a hangover like alcohol, it goes better with my meds than alcohol, it helps with pain, it relieves stress etc.

Try not to forget that most people who have sz don't smoke dope and many have never even tried it.

The rate of cannabis consumption by adults already diagnosed with bipolar disorder is also much higher than the general population, unlike sz no one is suggesting cannabis use causes it.

Short term psychosis related to cannabis is regularly seen in Australian hospitals, cannabis overdose and sudden cannabis withdrawal (in heavy users) this is rarely long term.

Genetic vulnerability is an idea borrowed from agriculture. In agricultural terms it describes a crops reduced resistence to disease because of a narrow genetic background.

In human genetics genetic vulnerability is the supposition that some one with x arrangement of genes and y environmental factors is more likely to develop z condition.

eg it is supposed that when genes for sz (x) are exposed to cannabis (y) sz (z) is more likey to develop. Although this relationship has been the focus of a number of tests, it remains unproven.

Now there are an impressive number of links to browse

[Dream of the iris]

I suppose the big question is how does one know if they have this "genetic vulnerability"?

[Storm Crow]

Would be to have a long talk with your grandparents. Ask about scandals- ax murderers and the like. Were any of their siblings or other relatives "odd"? What are the whispered about family scandals?

Since it is an inherited condition, it likely would show up more than once over the course of several generations. If they are curious why you're curious- just tell them an on-line friend was mentioning family odd balls/genealogical scandals in her family. And you were just wondering.

So you won't fib- here they are. There were a few sweet eccentrics on one side of the family -like the dude who felt that hitting a child's hand with a hanky was sufficient punishment for any "sin"- and he had a mess of kids!

On the other side of the family- My 8 x g-grandfather fled Sweden because he was a horse thief and then he and his brothers stole more horses here from the Indians! Great family!

I don't have schizophrenia, nor does anyone in my family. However, if I found that Great Uncle Joe killed Aunt Molly because the voices told him to, and two or three other relatives were a "bit off", I'd be DANG careful about pot and any other drugs.

My mother was bipolar. I have a tendency that way- I'm moody (but way more ups, than downs). Cannabis smooths my highs and lows. - Granny