Information provided for research purposes only of course - not in any way a substitute for professional advice!
Just about all the information you could ever possibly want or need is available through our Information page. If you don't find your answers here, that'd be the place to look.
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See also our Web Sales FAQ page.
- What batteries for 'slim' thick-oil cartridges, like the 'CCELLs'?
- No Owner's Manual? How do I use my first bong?
- What are my best options for batteries for 'slim cartridges' - especially those with longer battery life?
- I keep reading about vaporisers. How, when and why are they used?
- I was told that I can get a vaporizer/product through ODSP / Disability / Insurance - how does this work?
- What would happen if I put green in an espresso machine instead of coffee?
- Does a person who grows their own have any right to claim heat, hydro, fertilizer etc?
- What strain should I grow?
- How do I tell if my plant's male or female?
- What are the laws like in Canada?
- Do you wholesale?
- Do I have to be 19 to visit THC?
- I'm doing a paper/project on cannabis. I need more information / Can I interview you?
- Do you sell weed? seeds? crack pipes?
- How long does THC stay in your bloodstream or urine?
- How do grow-room fires start?
- How hazardous are 'grow ops?'
- When and how do I harvest my plants?
- How do I roll a joint?
- Does marijuana impair driving?
- Is today's marijuana really more potent than it used to be?
- Does marijuana cause schizophrenia? (or "psychosis")
Vaporizers are used because they are the healthiest way to ingest herbal medicine. In fact, a study done by M.A.P.S. (Multidisciplinary Association for Psychedelic Studies) and NORML (National Organization for the Reform of Marijuana Laws) a few years ago found that after vaporizers, rolled "joints" are the second healthiest method (presumably due to the self-filtering), followed by waterpipes and pipes (and that waterpipes don't offer much of a health benefit over pipes, if any). From what we know, due to the lack of vigorous burning a properly-used vaporizer will deliver much more of the desired active chemicals without the tar and other undesirable by-products of combustion. The difference in effect and efficiency are unmistakable.
There are two methods of vaporization today; the hot-plate (conduction) method and the hot-air (convection) method. The first is 'old technology,' and generally involves a heating element obtained from a soldering iron which is attached to some kind of a bowl and mounted inside of a vapor-holding jar. The bowl heats up, 'vaporizing' the herbs held within. This method has been shown (by the same above-mentioned studies) to be relatively inefficient, producing a high CBD:THC ratio in the 'vapor.' There are tons of companies producing hot-plate vaporizers. They are sold at a reasonable price (generally between $60 and $100 Canadian) and instructions are easily available to make your own. Due to the relative inefficiency and ineffectiveness of this method we do not recommend hot-plate vaporizing products, and we're sure the market will relatively quickly see a phasing out of them.
The second method, the hot-air method, uses a heat gun (commercially available for stripping paint, etc.) or similar air-heating device to pass hot air through the herbs, thus vaporizing the active chemicals. This method has proven to be far superior to the hot-plate method. There are many hot-air vaporizers on the market, from companies such as VripTech, Vapir, Vaportech and Vapormed. These range in price from around $150 to $800 Canadian. These products all perform well, each having certain advantages over the others, are really neat and high-tech, but cost an arm and a leg. The Volcano by Storz-Bickel in Germany is currently the ultimate vaporizer (see link below).
We have been working hard to bring hot-air vaporization technology to the average user and medical market - at a reasonable price. After lots of research and development, we think that the new THC Dominizer is the perfect best-of-both-worlds solution for hot-air vaporization. For under $20 Canadian (for the glass version, $50 for the steel) we provide a product that seems to work at least as well as the super-expensive vapo-gadgets with generally a much higher level of convenience and ease-of-use. For more information about the THC Dominizer and other vapo-related info, please check out: our Vaporization page.
Generally, it goes something like this: your Insurer / Counsellor informs you that you can purchase a vaporizer (or other item/s) and have the cost covered up to a certain amount... then 1) they provide you a letter stating this situation and amount and requesting an invoice prior to payment 2) we provide you with an invoice detailing the item(s) that you are seeking to purchase 3) the Insurer/Agency provides a cheque or similar method of payment, 4) you bring the cheque into the store and we exchange your new product(s) for that payment. It's truly generally that simple and relatively painless, and we have done this many times with and for folks like yourself! Please don't hesitate to inquire further with us at firstname.lastname@example.org or email@example.com anytime!
Sure, but it would be a very inefficient and wasteful way to do it. Cannabis' active ingredients are not water soluble, but will dissolve into oils, fats or alcohol. This dissolution actually makes the active ingredients more easily digestible, to the effect that such preparations can be up to and even more than twice as medicinally potent as, for instance, swallowing a bud as-is. Apparently some methods of preparation even alter the chemical makeup of the herbal material you are processing - converting some cannabinoids into higher-level ones even (eg. delta-9 THC being converted into delta-10 and even delta-11 THC). Higher level cannabinoids can be much more potent than lower ones. So your best bet may be to soak a bud in your favorite booze or gently simmer in butter or oil. From there, you can do whatever you want - add the alcohol to whatever drink you like, or cook/bake with the butter or oil. If you're into the coffee idea, you might be able to incorporate ganja and coffee cream or high-fat milk I suppose.
See also TCC's Medical Marijuana User's Guide.
Just got off the phone with my accountant cause I had to check it out. He says that the GENERAL RULE (there are exceptions, but not any that would likely apply in our situation) is that the only medical expenses that you can claim on your taxes are 1) prescription drugs with DIN number, prescribed by a licensed physician, and 2) bills from a licensed physician for treatment (which can include physician's billing for non-prescription medication). So if a licensed doctor could legitimately prescribe or bill you for cannabis, it could be claimed. It seems that there is no allowance for claiming expenses relating to producing your own medication or medicinal herbs.
See CCRA Interpretation Bulletin for part of their official stance, including:
"included in the account of a medical practitioner"...
[OR] "(a) [a few specific irrelevant items] which... a medical practitioner must have prescribed, but which a pharmacy or any other type of store may sell without a written prescription"...
[OR] "(b) the drugs (and other items), referred to in paragraph 118.2(2)(n), which a medical practitioner or dentist must have prescribed, and which must be purchased from a pharmacist who has recorded the prescription in a prescription record.
There is clearly some controversy, especially lately, surrounding this issue. Here's another opinion:
Yes. We can claim ALL expenses with our Medical Marijuana because we HAVE A PRESCRIPTION - the Exemption. If you have a note from your Doctor on his Prescription pad stating the words "I Prescribe Cannabis" for the above person, your life will be much easier.
Have him state your illness and the reason you receive benefit eg. "to treat the disabling effects of Multiple Sclerosis including leg spasms, pain and nausea".
On a separate piece of paper, write the words:
*Note: This is an over the counter drug. It is a Narcotic for Medical use only. Prescribed by Dr.______ and The Ministry of Health for the Possession of and Production of (where applicable) Medical Marijuana. Then at the bottom add your Possession # and Production #'s where applicable.
Next write your Prescription amount, how much you are allowed to grow and the difference between growing and buying.
This is a NON-REFUNDABLE TAX CREDIT. Please TEACH your Accountants.
I haven't been on line much lately or would have answered way back... I have been battling very bad health due to excruciating pain in my face from the lack of Cannabis - Again. Hope this helps you guys.
-Thank you Alison! -Dom
You should consider what benefits you get from marijuana, and aim for strains that have the chemical make-up that helps you most, while of course taking into consideration such other important factors as yield and how long each strain takes to finish. Cannabis, like everything else in the world has a great deal of genetic variation within its species, causing different growth characteristics and effects. The most useful disctinction is between "Indicas" and "Sativas." Sativas grow lankier and produce more of an "up high" or "euphoria," seem to stimulate and/or enhance mental activity more than the Indicas, and are said to be better for stimulant, muscle relaxing, anti-epileptic, anti-emetic, anti-inflammatory, appetite stimulating, bronchio-dilating, hypotensive, anti-depressant, and analgesic effects. Indicas typically grow shorter and chunkier, are said to produce more of a "stone" and "body buzz," and are considered to be better for conditions such as those involving pain, anxiety, microbial infection, increased ocular pressure and insomnia. There are approximately 60 identified cannabinoids (the medicinally active chemicals in marijuana), THC (a.k.a. delta-9 THC) being but one of them. Sativas may have 100% of their cannabinoid content in the form of delta-9-THC. Indicas may have 0% THC and very high levels of other cannabinoids like CBN (cannabinol) and CBD (cannabidiol). The best part of this dynamic feature of the cannabis species is that Indicas and Sativas can be cross-bred, and most available strains possess mixed qualities, characteristics of both Indicas and Sativas. Some are considered Indica dominant, some Sativa dominant, etc. So the possible variability in cannabinoid profiles is virtually infinite. Amazingly, we've been seeing strains lately that appear to have growth and appearance characteristics of Indicas while having cannabinoid profiles more in line with Sativa strains, and vice-versa! And different cannabinoids appear to work both individually and cooperatively - CBN for instance lessening the psychoactive effects of THC. The possibilities are apparently endless. So when you're picking your seeds, you might choose an indica like Afghani, a sativa like Thai, or something "in between."
See also TCC's Medical Marijuana User's Guide.
That's easy... they look very different. First, of course, you have to know a little about the life cycle of cannabis plants. Generally, marijuana plants produce their flowers, thus indicating their sex, when the plants sense that they are receiving somewhat less light per day than a genetically programmed threshold level, as the growing season progresses and the days get shorter. If you want to trigger your plants to flower, generally you must provide an environment in which they receive at least 12 dark hours per day (many people allow their plants to grow larger by allowing only 6 or fewer hours of darkness per day for a little while before triggering them to flower). Both male and female plants produce flowers. The flowers of each sex play a role in the plants' sexual propagation. The male plant produces pollen sacks that open when the pollen is ready. The female flower is made up of seed pods, each of which has two "hairs" protruding from it. These hairs exist to catch the pollen dropped by the male plant, allowing the female plant to produce seeds. If your female plant produces seed, there isn't really anything left of the flower to smoke. If no male is present, the female flowers will just keep getting bigger and more potent, packing on more and more empty seed pods, until harvest time.
While this website primarily serves our retail business, we do have a wholesale division through which we distribute products to other retailers and dispensaries for resale. If you represent a dispensary or retail business registered in Ontario or elsewhere in Canada, please inquire via email (firstname.lastname@example.org) and we can get you set up with a Wholesale Account Application and give you a better idea of pricing and availability (we have around 30,000 products in our retail product database, but not quite that many are available for wholesale).
Of course, we carry many different types of products in our store and on our website - many of which are completely unrelated to 'adult activities' and so SHOULD be available to folks of all ages (as should, arguably, much of the information that we provide). HOWEVER, in these confusing days of changing legal climate there is a need for increased care and so we have recently had to modify our age-limit to only allow those aged 19-and-over to shop at our store and access our website, etc. Our apologies for any inconvenience caused by these policies, especially in these chaotic times of transition!
We're here to serve as a resource centre as much as a retail store. I'm happy to contribute to school, research and (perhaps a bit more selectively) media projects, as our schedules permit. I consider it a pleasure, an effective method of advertising and public relations enhancement, good practice, and a duty to contribute however possible.
In fact, I'd like to specifically invite inquiries from people who are interested in performing relatively anonymous, preferably form-based research, drawing on the knowlege and experiences of willing members of the Toronto Compassion Centre and/or other medical marijuana organizations.
Let's start with the crack pipes and other similar requests... best answer I suppose would be "Go away, get off the crack!" That stuff does no one any good. While we are totally sympathetic about the potential harm reduction benefits of providing 'safer crack smoking' items for example to prevent the spread of disease caused by lip-cutting or lung-bloodying make-shift crack smoking paraphernalia, wading into this touchy subject is not the place of a hemp store. We cannot afford to take the risk of helping anybody that comes in requesting, or obviously seeking, any items for 'hard drugs.' Please contact the appropriate organizations (drug users' groups and detox facilities for example) for help with this kind of thing.
Weed? Of course we can't break any laws. We want them changed, but wouldn't be doing anyone any good from prison! The day will inevitably come when we wake up out of this nightmare of waging war on, and punishing, our own people for private, harmless and widespread behavior, but until then, sorry, we're not stupid or crazy.
Everyone should visit Amsterdam (and Switzerland, and much of the rest of Europe), by the way. It's amazing to leave here thinking we live in the land of the free and come back realizing that we are so very much more "stuck up" and restricted in such important ways than most of the civilized world!
For those of you seeking medical marijuana, there are "Compassion Centres," or "Buyer's Clubs" everywhere now. If you are in need, please feel free to ask for help or consult such organizations as the Toronto Compassion Centre, or the Canadian Cannabis Coalition to find the compassionate organization nearest you, or one that delivers (some actually do). Be picky in your search for a centre; there certainly are and/or have been a few "centres" that don't care to conduct themselves with the actual compassion or concern for legitimacy required in such a situation.
Seeds? Even though the sale of seeds is quasi-legal and has long been tolerated (they contain no measurable THC and marijuana is no longer classified completely as an "illicit drug", have been openly available from dozens of companies across Canada and hundreds around the world for many years), we still choose to not sell them out of THC. Toronto Police asked this of us years ago, and until we hear specifically otherwise, sorry no seeds. Please check with www.sacredseed.com - Sacred Seed, Exotic Seed and Houseplant Shop (in downtown Toronto).
I grabbed this off someone else's web site for you (toad.net or something like that) because I found it quickly and it sounded pretty consistent with my research and our experience.
THC (the most prevalent psychoactive compound in cannabis) is highly lipid soluble and quickly passes from the blood to the brain and other lipid-rich tissues. It is metabolized in the liver (Frances, 1998). However, the liver is not able to metabolize the THC in the body very quickly; the unmetabolized THC binds to the fat cells in the body. Between periods of active marijuana use, the fat-bound THC is slowly released back into the blood (Doweiko, 1996).
THC is estimated to have a half-life of five days; it diffuses widely throughout the human body and remains there for quite some time. An occasional user may fail a urine test (test positive) three days after smoking a single joint. A heavy user may test positive after abstaining from marijuana for more than a month (Schlosser, 1994).
There can be hazards involved with indoor gardening. The risk of fire, water damage, electrical shock and chemical poisoning must be considered and addressed by those who choose to "grow their own." Often, the least understood and most dangerous hazards are also the easiest to avoid.
Gardeners should use organic fertilizers and pest control whenever possible and avoid contact with any toxic chemicals, both through the growing process and in the finished product. Gardens should be arranged in such a way that any spills or floods will be safely contained. Electrical safety should always be kept in mind. Electrical equipment and fittings should be installed and maintained properly. Also, water and electrical equipment can be a very dangerous mixture, and growers should be careful to avoid being burned by (or staring at) hot bulbs.
Perhaps the most common (and avoidable) cause of fire in a garden is "arcing", which occurs when current flows through an improper electrical connection, sparking from one contact to another. This can heat up the fixture, eventually causing it to break, explode or melt and allowing the arcing or super-heated pieces to ignite nearby flammable material. Gardeners must ensure that any High Intensity Discharge (H.I.D. - e.g. High Pressure Sodium or Metal Halide) lamp (bulb) being installed is screwed in properly, making good contact with the little metal tab in the light fixture's socket. The tab may have been pushed in further by the last bulb that was used, and bulb bases are not always identical - some may screw deeper into the socket than others. The bending of this tab itself can be hazardous immediately and/or in the long term, and is not recommended for anyone who is not professionally trained. Instead of bending the tab themselves, gardeners who notice a malfunction or are otherwise concerned about a less than perfect contact in their electrical setup are recommended to either have their equipment professionally inspected and adjusted, or purchase a new one. They're not very costly and the peace of mind's well worth it! Many components of a grow room should be replaced periodically to prevent not only safety related problems but health and production concerns.
Generally there will be some period of warning before a catastrophic failure. Any equipment that produces an unusual buzzing, flickering, smell or heat should be disconnected and serviced immediately (H.I.D. ballasts do normally emit a quiet and steady buzz, they do get warm, and the lamp may flicker a bit while the unit is warming up).
Our governments and media ignorantly and cynically enjoy repeatedly sensationalizing the 'grow op' issue without ever reasonably pointing out that prohibition, rather than the harmless act of growing a plant, is invariably the 'root cause' of any danger related to gardening. So we continually hear about 'booby traps,' 'grow-op fires,' 'toxic mold,' 'hazardous chemicals,' and even explosions when our confused 'leaders' talk about marijuana. As with virtually all drug-war hysteria, the assertions and insinuations about these dangers are never based on reason and research. The following graphic may shed some light on the truth:
Many interesting comparisons and conclusions can be made to and from these statistics. One interesting comparison is that, according to the the RCMP (and the Canadian Department of Justice and the Angus Reid Group, 1991), 23-34% of Canadian households have firearms in them. I wonder how many have 'hazardous chemicals,' and/or explosives, and/or fires, and/or knives?
When? - When your plants are finishing up, the "hairs" will start to darken in colour and curl up. More important as an indicator of ripeness, the "resin glands" will start changing from clear to somewhat more milky or brown in appearance. A real handy tool for examining the glands is a "30x (or 60-100x) pocket microscope," available from garden supply shops like ours and Radio Shack / "The Source by Circuit City". Many people harvest different parts of the plant bit by bit as the top may finish first with lower bits finishing soon after, but this may be inefficient if you already have other plants ready to put under your lights.
What to do? You're going to first get rid of the 'useless' stuff - cut off the "fan leaves," which are the big full leaves on long stalks. The other relatively useless part you will eventually discard along with the fan leaves is the larger stalk / branch pieces that are, like the fan leaves, lacking in 'glands' and therefore potency. After removing the fan leaves, you next want to cut off all the flowers and 'manicure' them - cut away the little leaves that are growing out of the flowers. These "bud trim" leaves do contain some active ingredients, so you should keep them for cooking or other processing, but the big leaves elsewhere on the plant are, again, relatively useless. Keep and consider using any leaf that appears to have resin glands on it, but the flower 'buds' are obviously the important part.
Once you've got all the buds (flowers) cut off and 'manicured,' you want to dry them. You can just lay them, spread out, on a screen (or, less desirably, a flat surface) to dry, or you can try to extend the drying process by putting them in paper bags (or another not-airtight container like a wooden box or drawer). Drawing out the drying process makes for better flavour and potency, but you have to be careful to avoid mold at all costs. You must be careful to encourage even drying throughout. The drying buds have to be checked and spread out, repositioned regularly to avoid any wet pockets that will cause mold to grow. You might want to leave the bags wide open sometimes and folded shut at the top others, depending on such factors as atmospheric as well as bud humidity. You must make sure to dry them to a point where there's no chance for mold, and this generally takes a few days. Remember that you are likely to get to a point where the outside of each bud feels fully dry and crispy, but the inside will still have a high level of moisture - the paper bag method helps this by encouraging even drying. Many people will put their mostly-dry buds in an airtight container (plastic bag or jar) for a little while (minutes to hours) to allow re-distribution of moisture throughout the buds, then put the now-less-dry feeling buds back into the drying process.
Once the buds are dry enough that there is no chance of mold (twigs must snap, not bend!), It is wise to put them in a solid airtight container like mason jars, kept in a cool and dark environment. And keep in mind that even after they're properly dry, it is best to allow the buds to continue to "cure" for a couple weeks or so - no work involved, just waiting and making sure they're safe from mold etc. - because the active (and inactive) chemicals and flavors really do change and improve over the curing period. Fully cured buds can be stored in mason jars or airtight bags for months and still be excellent. Refrigeration isn't necessary after proper curing, unless you're stuck with buds that are less than ideally dry and have to refrigerate or freeze them to avoid mold. This likely only applies to situations where it is necessary (for financial reasons perhaps?) to preserve weight.
Some people prefer to dry the plant before manicuring, generally by hanging them upside-down on strings in an appropriate environment (upside-down because the branch structure provides a convenient hook, not because of any imagined movement of active ingredients due to gravity). Most growers we know, however, feel that the manicuring is far easier when the plant is fresh rather than dried with leaves curled up, etc.
It is against the law to drive while under the influence of marijuana. It has always been assumed that cannabis, like alcohol, impairs the perception, coordination, reflexes and judgment necessary for the safe operation of a motor vehicle. And, of course, there have been governmental studies addressing the question: Does marijuana impair driving? Interestingly, however, the findings do not necessarily support popular opinion....
On the one hand, the California Department of Justice has found that marijuana undoubtedly impairs psychomotor abilities that are functionally related to driving and that driving skills may be impaired, particularly at high-dose levels or among inexperienced users. "Marijuana and Alcohol: A Driver Performance Study", California Office of Traffic Safety Project No. 087902 (Sept. 1986).
Contradicting these conclusions, however, are two [(U.S.)] federal studies.
The U.S. Department of Transportation conducted research with a fully interactive simulator on the effects of alcohol and marijuana, alone and in combination, on driver-controlled behavior and performance. Although alcohol was found consistently and significantly to cause impairment, marijuana had only an occasional effect. Also, there was little evidence of interaction between alcohol and marijuana. Accidents and speeding tickets reliably increased with alcohol, but no marijuana or combined alcohol-marijuana influence was noted. "The Effects of Alcohol on Driver-Controlled Behavior in a Driving Simulator, Phase I", DOT-HS-806-414.
A more recent report entitled "Marijuana and Actual Performance", DOT-HS-808-078, noted that "THC is not a profoundly impairing drug....It apparently affects controlled information processing in a variety of laboratory tests, but not to the extent which is beyond the individual’s ability to control when he is motivated and permitted to do so in driving".
The study concluded that: "...An important practical objective of this study was to determine whether degrees of driving impairment can be actually predicted from either measured concentration of THC in plasma or performance measured in potential roadside "sobriety" tests of tracking ability or hand and posture stability. The results, like many reported before, indicated that none of these measures accurately predicts changes in actual performance under the influence of THC...".
The researchers found that it "appears not possible to conclude anything about a driver’s impairment on the basis of his/her plasma concentrations of THC and THC-COOH determined in a single sample".
Note: "THC" stands for Delta-9-tetrahydrocannabinol, which is the intoxicating ingredient in marijuana. THC is fairly quickly converted by the body into inert metabolites, which can stay in the body for hours or even days. It is these metabolites that police blood tests in DUI arrests detect and measure. In other words, (1) marijuana may not impair driving ability at all, and (2) the blood "evidence" only measures an inactive substance which may have been there for days.
Another common drug-war fallacy is that marijuana has somehow become more potent (and hence, more dangerous! Run for your life!). This is yet another ridiculous claim, for the most part. Of course, even with the restrictions placed on the community that cultivates it, there has been some 'natural selection' with the intention of increasing the potency of Cannabis plants over the years. And there have been some improvements in the processes and products used to cultivate Cannabis plants, like virtually all other cultivated plants, mostly with the goal of increasing yields but surely also occasionally with the impact of somewhat increasing the potency of the end product. So perhaps here and there, once in a while, some better plants have been developed. But for the most part, marijuana is still the same plant, and is still grown the same way (under the sun and with natural or otherwise commonplace fertilizers) all over the world as it basically always has been. And if occasionally there has been a plant or many grown with an increased level of active chemicals in it, it would be hard to consider this a bad thing! The more active ingredients, the better the medicine and the less one needs to inhale or otherwise ingest.
But in truth, if one were to actually consider the research and realistic facts of the situation, one would find that the marijuana of today is generally not really any stronger than that of days long gone by. If you consider the testing procedures and the actual facts (such as those found in "Marihuana Cultivation in Canada: Evolution and Current Trends - November 2002 Criminal Intelligence Directorate - Royal Canadian Mounted Police - November 2002" which state that "The THC content of the 3,160 marihuana samples analyzed during the three-year period varies considerably. Although the highest value recorded was 25 percent, the yearly country-wide averages are much lower: 6 percent for 96-97, 5.5 percent for 97-98, and 5.7 percent for 98-99 (figure 7). In fact, almost a third of the samples were under 3 percent."), you quickly realize that the facts are far less potentially worrisome than the lies.
Oh brother. It's pretty unbelievable that we even have to address this ridiculously bogus nonsense. After all these decades of lies and idiotic propaganda, the thought that anyone could actually take this recent dose of reefer madness seriously is almost hilarious. As with all other reefer madness propaganda, all it takes is a millisecond consideration of the world around us to answer for yourself how believable this nonsense is... just ask yourself 'with the use of cannabis clearly widespread and arguably moreso than ever before, are there morgues full of bodies and/or hospitals full of cannabis-induced-schizophrenics, streets full of weaving marijuana-impaired drivers, etc., to indicate that assertion X might be true?' The answer should be pretty quickly obvious. And yet this nonsense has been all over the newspapers and flying out of the mouths of the ignorant all over the world. Unreal. Here's an exerpt from a recent, more intelligent, newspaper article that takes a slightly more realistic stance.
From: Vancouver Sun, Dan Gardner (Ottawa Citizen Columnist), The Real Risk Is In The Uninformed Warnings About Risk, http://www.mapinc.org/drugnews/v07/n956/a08.html?76342 :
"A paper published in the British medical journal The Lancet recently found that users of marijuana have "an increase in risk of psychosis of about 40 per cent" compared to those who had never used marijuana. The most frequent users were at 50-per-cent to 200-per-cent greater risk.
There are many things to note about this study.
First, it's not new. It's a meta-study of existing work that supports earlier conclusions. There are doubts about the methodologies of some of those papers, which has been written about before.
Second, as the authors were careful to note, the study does not prove marijuana causes schizophrenia and other forms of psychosis. It shows they are associated. The researchers tried to control for various factors but they can't rule out the possibility that something else may be at work.
But let's leave all that aside. The issue at hand is risk, not marijuana. So let's assume that the Lancet paper really does show that marijuana causes psychosis. And let's assume the increased risk really is as high as 200 per cent. What does that mean?
Nothing. Or rather, it means nothing by itself.
If the lifetime risk of being crushed by an asteroid were to triple, we would ignore it because the original risk is so tiny. But a tripling of the lifetime risk of getting cancer is serious because the existing risk is big. So to make sense of the increased risk of psychosis, we have to know what the existing risk of psychosis is. Without that, these stats are scary but meaningless.
Yet many journalists did not provide that key piece of information, while others buried it as if it were a trivial detail. Even an editorial that accompanied the paper in The Lancet only mentioned the relative risk.
An Agence France-Presse story that appeared in some CanWest newspapers did modestly better: "The report stresses that the risk of schizophrenia and other chronic psychotic disorders, even in people who use cannabis regularly, is statistically low, with a less than one-in-33 possibility in the course of a lifetime."
That's not a lot of information, but it's enough to work out the basic numbers: According to this paper, someone who never uses marijuana faces a lifetime risk of around one per cent; a light user's risk is about 1.4 per cent; and a regular user's risk is between 1.5 and three per cent.
These are significant numbers, but they're not nearly as scary as the numbers that got the headlines. And as far as I can tell, not one news story anywhere in the world reported them in full.
And that, I'm sorry to say, is typical.
Last year, a study found, in the words of one newspaper article, that women who use the Ortho Evra birth-control patch "were twice as likely to have blood clots in their legs or lungs than those who used oral contraceptives." Twice the risk: In newspapers across North America, that was the only information readers got. It sounds big. No doubt some women found it quite frightening.
An Associated Press story provided the missing piece of the puzzle: "The risk of clots in women using either the patch or pill is small. Even if it doubled for those on the patch, perhaps just six women out of 10,000 would develop clots in any given year . . . ."
The AP story was carried widely across North America but many newspapers that ran it, including The New York Times, actually cut that crucial sentence.
We face lots of risks in life, including the risk of getting bad information about risk.
More to come, always.
Please e-mail any questions, comments or additions.