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Pot can cause mental illness says The Lancet

August 7, 2007

New research from reputed British medical journal The Lancet has busted some hard held beliefs that cannabis is safe. Cannabis has been linked to mental illness. The findings:

Using marijuana seems to increase the chance of becoming psychotic, researchers report in an analysis of past research…the new review suggests that even infrequent use could raise the small but real risk of this serious mental illness by 40 percent.

And those who use the drug regularly could increase their risk factor by 50 to 200 per cent!The study is reportedly a “comprehensive meta-analysis to date of a possible causal relation between cannabis use and psychotic and affective illness later in life.” This new research has examined 35 studies that “tracked tens of thousands of people for periods ranging from one year to 27 years to examine the effect of marijuana on mental health…they looked for psychotic illnesses as well as cognitive disorders including delusions and hallucinations, bipolar disorder, depression, anxiety, neuroses and suicidal tendencies.

However the study acknowledges:

There could be something else about marijuana users, “like their tendency to use other drugs or certain personality traits, that could be causing the psychoses…

The findings of the study will not exactly be engraved in stone but they are still likely to shake the comfort zone of cannabis users. Most sensible people don’t want to take chances….why, more research could unravel something worse…studies on this subject are ongoing. And the research seems to be pointing in one direction – that we do not know enough about the harm of cannabis use can cause.

Is Cannabis safer than alcohol and tobacco?
Although a Lancet study as recent as a few months ago said that tobacco and alcohol (the socially accepted drugs) were “more harmful than cannabis,” I feel they might have revised this opinion now. After all, who has heard of tobacco or alcohol being related to mental illness? Yes, I have heard of those with mental illness getting addicted to alcohol, but not the other way round. If this study is corroborated by further research and a direct link established between cannabis and mental illness, then it would confirm my suspicion that cannabis is more harmful than either tobacco or alcohol.

Britain changing its policy on cannabis
Britain is taking this study seriously. It says here:

As cabinet ministers in the UK fall over themselves to tell all about their cannabis-taking younger days, Gordon Brown’s Government begins its review of the classification of cannabis, with the probable outcome of relabelling it a class B drug of misuse. Possession would then become an offence likely to lead to arrest and perhaps a jail sentence. Cannabis was downgraded to class C in 2004, which meant that the penalties for possession, production, or supply were reduced.

How legal is it round the world?
You can get information of the legality of cannabis in different parts of the world here. Most countries have some kind of laws regarding its cultivation, use, possession, or recreational use. Laws regarding possession of cannabis are very strict in Asia. It is important to note that laws are getting more restrictive in some western nations, like Denmark for instance (and Britain). Its banned in Sweden and Switzerland, even for personal use. However, in some parts of Australia its legal. In some countries (Canada) there is a movement to legalize cannabis, but I feel that this study could put a dampener on these efforts.

What about India?
Over here we do have less cause for worry as our laws have banned cultivation, possession and use of cannabis, but on the other hand there is an increasing number of urban youth falling prey to drugs, and not just cannabis. In fact of late, this phenomena called rave parties has been in the news. After a rave party was busted by the Pune police a few months ago the media attention went on for weeks after the event. Before then a lot of people had never heard of a rave. Now everyone knows that the term is associated with drugs…and not just cannabis.

Can you believe it, if you google ‘rave parties’ five out of ten results on the front page are from India!!

It’s ironic because apparently the term rave is not so respectable in the west anymore. The rave culture as it’s called started to decline in the 1990’s…in India one doesn’t know how widespread or how popular it is, but its certainly ‘cool.’ Just a few days ago police busted a rave party in Mumbai. Most rave parties are held on farmhouses of the well-heeled and are generally kept under wraps.

I also found a travel site trying to lure tourists to come to Goa for its rave parties!! Sure, there was no mention of drugs…

What is worrying is that a lot of people here seem that there is nothing wrong with raves or drugs. I am definitely not taking a moral stand here…but from the health point of view I think some serious doubts have been raised..and its better to be safe than sorry.

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21 Comments leave one →
  1. August 7, 2007 6:46 pm

    Thanks for raising our awareness of marijuana. It’s still the drug of choice in the southern part of the US for many underage youth who can’t yet buy alcohol. I also worry about the damage it does to the organs, especially the lungs, heart, and brain.

    I’ve smoked pot, many years ago, and it made me feel anxious. I’m an anxious person anyway, so maybe there’s some correlation between a person’s current make up and the drugs they consume. as you suggested.

    Likewise, alcohol for me, and for many others, acts as a depressant. While
    it doesn’t cause depression per se, it can worsen an incipient depression.

    I guess I’ve had my head in the sand about India, because I’m very surprised by the news of raves there. Are community leaders trying to educate the kids about the dangers? Do many parents know about raves?

  2. August 7, 2007 7:10 pm

    This is entirely interesting news, Nita. I would not have expected anything like it. Thank you for posting it!

    I imagine that even if this meta-study is borne out by further research, it will still take years for the risks associated with cannabis use to become widely accepted as fact. I say that because I’m under the strong impression that it is almost universally believed by people my age (50) and younger that cannabis has no major side-effects.

  3. August 7, 2007 7:16 pm

    Maria, over here parents usually do not know what their kids are upto! Whether its dating or parties or smoking or drinking, youngsters tend to hide it from parents as the society is very conservative.
    The more affluent crowd holds raves but youngsters and young professionals from all sections of society participate.
    The police are coming down hard on this trend but as its not open its difficult to stop. And no, there is no campaign as such by community leaders but yes there are awareness programmes held in educational institutions.

    Paul, yep I think there is widespread belief that pot is harmless and people are going to pooh pooh this study. There is already a lot of criticism against the findings, but I feel that any scholarly work should be given importance.

  4. August 7, 2007 7:30 pm

    In the article they also said, “The researchers said they couldn’t prove that marijuana use itself increases the risk of psychosis, a category of several disorders with schizophrenia being the most commonly known.” Correlation doesn’t prove causation. It’s like saying the rise of cabbage sales caused the crime rate to increase in NY. Pot does not cause mental illness. This research simply alludes to it, which does not prove causation. But if a person already has mental problems or some other underlying issues, and turns to drugs, may it be tobacco, alcohol, pot, cocaine, etc. (usually it’s the harder ones because nicotine, pot and alcohol can only go so far) to escape from their problems and use them regularly, then they not only have to deal with their regular problems that made them start up again, but also their psychological and physiological addiction to those drugs. I think the only drug that can “cause” mental illness would be Datura (Angel’s Trumpet) because it wipes your slate clean and the effects are permanent. I think one thing that research study did was to show that people with underlying problems and illnesses are more likely to turn to drugs than others. And of course, meth, which is a horrible concoction.
    Too bad the main intent of that study was to scare people, rather than inform them. Thank you for posting it, though. You did a great job linking to other sources and giving an overall picture of what’s going on with all the bans around the world. 🙂

  5. August 7, 2007 7:53 pm

    dianarn, after reading your comment I felt I had not done a comprehensive enough job, and I have added one more link. The para on: ‘How legal is it round the world.’
    And as for your views, they are welcome. 🙂 I know there is some controversy about these findings…

  6. August 7, 2007 8:10 pm

    I don’t think the Lancet is in the business of trying to scare people, Dianarn, although I respect that you might differ with me on that opinion. Still, from all that I’ve ever heard of the Lancet, they are highly regarded as a source of accurate information.

    By the way, Nita, I took the liberty of mentioning you on my blog this morning. I hope you don’t mind.

  7. August 7, 2007 8:27 pm

    Paul, how could I mind? 🙂 I am rather speechless in fact. Thanks.

  8. August 8, 2007 12:34 am

    Mark Hoofnagle at denialism blog posted a really good article about this study titled DoesSmoking Cannabis Cause Schizophrenia? that talks a lot about correlation versus causation. He takes the study and associated data and does a thorough analysis of the validity of the study itself.

  9. August 8, 2007 9:43 pm

    These are very interesting findings – thanks for posting about this comprehensively, Nita!

    The denialism blog really does a good job of separating the hype from the factual findings of the study.

    I think causation and correlation are inherently complex and important factors that limit the extent of meaningful research we are able to do today. I wonder if very long into the future, we would be able to isolate gene patterns that are responsible for traits and characteristics (ranging from intelligence to mental illnesses), and then apply influencing factors (like drugs, other stimuli) to study their effect on these patterns – in isolation – i.e. on artificial organisms created just for the sake of the research.

    If we’re able to do that, then a whole universe of meaningful research will open up and we will have many exciting discoveries!

  10. August 8, 2007 10:03 pm

    Mahendra, yes, I too am fascinated with the idea that we as human beings are doing so much research on genes today. Every day one reads in the newspaper something or the other about some new discovery in the field of genetics and I am sure that a day will come when the mysteries of the human condition will be unraveled.
    However talking very generally I think the gene needs to be there…before any external factor influences, at least that is what I believe. In studies when they say that a certain percentage of people are affected by say a single external factor (and if it is different from the control group then I guess it becomes a finding )…maybe its the gene that triggers it off in those people. But then genes can mutate too…

  11. August 10, 2007 10:08 pm

    I don’t believe every ‘scientific’ study that comes out about marijuana. According to some people, marijuana makes you go crazy and punch babies. Then of course, there is that priceless gem about marijuana being a ‘gateway drug’ that leads to harder drugs.

    To put it simply, I would love a world where every alcoholic beverage was replaced with a joint. Mary Jane smokers sit around and talk about God, the Universe and Jimmy Paige’s guitar solos. Generally, they tend to be more easy going, relaxed, and peace-loving folks that don’t care about race or religious differences and are always open to ideas. Marijuana is not a big bad drug and from what I’ve read, is far less damaging than cigarettes, alcohol or even red meat.

    But of course, we can only dream of a world where a guy who likes to hit a bong on the weekend isn’t treated like a criminal.

  12. August 10, 2007 11:55 pm

    //the gene needs to be there…before any external factor influences//
    Exactly. If such experiments were possible, we would have isolated psychotic gene patterns from non-psychotic ones, and then study the effects of the influencing factor on both. This is the only way we can reach conclusive results on this kind of research.

    Such artificial organisms will not mutate in the lab. That’s what I’m hoping for!

  13. August 11, 2007 2:38 am

    Check out for both sides of the argument.

  14. Jeff permalink
    August 13, 2007 3:14 am

    Unlike you I have seen alcohol turn a sane/normal man into a psychotic. Alcohol is much more dangerous to the brain it kills brain cells. THC is only temporarily stored in the fat surrounding the cell. That seems much less harmful to me. Marijuana has stopped my seizures and my last eeg came back normal. First one since I sffered a severe head injury at age 4 resulting in petit ma, a mild form of epilepsy then I started smoking marijuana at age 18 and now at 54 I am seizure free with a normal brainwave patter. Thank you cannabis. Peace be with you.

  15. Jennifer permalink
    August 26, 2007 12:08 pm

    In the above article, you ask the question, “After all, who has heard of tobacco or alcohol being related to mental illness?”. Well, LOTS of people suffer from mental illness directly caused by heavy alcohol abuse. Many nursing homes in the West have at least one or two patients suffering the effects of pre-senile dementia. My mother used to be a nurse, and over the course of her career cared for many people ranging in age from their early forties to late sixties who had all the classic symptoms of dementia; they had the brains of ninety year old people, but were quite young, and virtually all had been alcoholics in their youth. Alcohol can cause and/ or exacerbate depression. And as far as “being related to mental illness”, how tenuous a link do you want to make? Cigarette smoking is one of the leading causes of erectile dysfunction in men. Sexual dysfunction can cause depression in some men. Could you say the cigarettes caused their mental illness? I guess it depends on your rhetorical strategy, doesn’t it?

  16. August 26, 2007 12:09 pm

    Well Jennifer thanks for enlightening me on the subject of the relationship of alcohol and cigarettes to mental illness. I confess I was quite ignorant of the issue. I was talking from the point of view of a layman. I guess most people are not aware of it…but I don’t know.
    Ofcourse I had heard that if you are already depressed and you take alcohol it can make you more depressed but no, I did not know about dementia.

  17. Jacob Mack permalink
    August 25, 2008 3:33 pm

    Hello all. I have read all your posts and links of reference as well. I can see how each of you may have certain veiwpoints based upon your scientific literacy and/or area(s) of expertise. Now when the prestigous Lancet and Nature write such glowing commentaries it seems difficult to dispute such findings without a thorough background in either biochemistry, neurobiology or actually, statistics.
    I have a background in neurobiochemistry, Psychology and I have taken and utilize stats as well. Lancet has misinterpreted its findings and Nature is just regurgitating those findings similar to a common lay persons news media outlet. The confidence intervals (CI) respective correlations only indicate that many habitual users have pre-existing conditions and higher risk factors to begin with, not that the steroid like compound, THC (cyclooxegenase inhibitor, prostaglandin inhibitor, anti-inflammatory compund) has a causal effect in any mood disorder, and most of those descriptons come from the Diagnostic Statistics Manual IV TR and trust me alot of controversy exists regarding the use of this manual in describing anf diagnosing mental illness. Furthermore, many cjronic drug abusers use several other drugs, most mentally ill people abuse many substanes before the potential pot use ensues at the onset of one or more symptoms. I am not advocatinf drug us by our nations’ youth or denying that smoking pot may lead to harder drugs, however, by itself marijuana is not an especially dangerous drug and does not cause affective disorders or make on shcizophrenic. I have done extensive research in class, 20 page research papers, peers who smoke habitually and I have looked closely at the Lancet publicaion. The stats do not add up to their assumptions and the biochemistry just is not there. Also, marijuana does act as a mild dose dependent hallucinogen as ot modulates neurotransmitters like dopamine, serotonin and glutamate and Gamma Amino Butyric Acid GABA. Individual, dose dependent subjective experiences do vary;some do get anxiety attacks, while others do not and some suffer temporary side effects dependent on environment.

  18. Jacob Mack permalink
    August 25, 2008 3:35 pm

    Alcohol decreases dopamine production and may cause severe brain atrophy and inreases Alzheimers risk.
    Severe alcoholics may develp[ B vitamin deficencies and have low red blood cell counts caused by abd coupled with poor liver function and renal impairment.

  19. vasudev permalink
    April 1, 2009 11:47 pm

    interestingly, i used to pot while i was an engineering student some 25 odd yrs ago. actually many of my pre-exam nights were spent in smoky pot-filled rooms. if i remember, pot used to be an excellent brain stimulator. we had a group of guys who would sit around and discuss serious topics over pot. our method was to audio-record a recital of a boring theoretical subject in the day time. then late at night a room full of us potters would lie down on the floor and listen to a play back. every time we did this the mind used to come out creatively and focus effectively on even mundane passages. every word would be discussed threadbare and fixed in the mind, the basics cleared effectively. but this method often impaired the speed of study which deficiency we got over through regular potting, of course.

    i remember the nights spent on hostel terraces with a line of potty guys passing on front twirled scissors cigarettes filled with pot, discussing the stars and constellations and falling deeply in love with mother nature. everything used to seem magnified, detailed…even text books. we guys used to go on our own moon missions and with soft english music playing in the background it used to be a great experience.

    throughout my course in mechanical engineering never did i drop a paper but always earned at least a place amongst the first 10 toppers. all my potty friends too were likewise lucky. no backs, all thanks to pot! pot which made our thoughts clear and minds imaginative/inquisitive/questing. but i was always uncomfortable with pot. had a fear of being found out (deep red eyes) some sudden middle-of-the-night-hostel visit from parents/relatives with bad tidings. had the lurking back-of-the-mind fear that my hostel warden might find out. decided to kick the habit the moment i left college and kick it i did some 25 yrs ago. no regrets! had my fun. nowadays there are so many researches on all sorts of odd subjects! 5 college yrs of regular potting, drinking, smoking did not make me any worse than the average man you meet at any regular global conference of the technocrats.


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