Talk:Health issues and the effects of cannabis

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[edit] Mistake in LD-50?

On the LD50 of THC page it says LD-50 in mice is 42g/kg INTRAVENOUSLY not through inhalation. I doubt the value quoted here, since inhalation usually leads to lower intoxication than oral consumption. 84.132.132.83 00:55, 20 November 2006 (UTC)

[edit] Citation regarding cancer

Referring to this Marijuana use and increased risk of squamous cell carcinoma of the head and neck.

The study[1] states The results need to be interpreted with some caution in drawing causal inferences because of certain methodological limitations, especially with regard to interactions.

I don't think this is a reliable source because of this statement and the lack of information on the methods used in the study. HighInBC 13:44, 5 September 2006 (UTC)

Why don't you add your evidence to the article instead of removing a relevant, sourced statement? The study states the results need be interpreted with some caution in drawing causal inferences. The statement 'One of the view studies to show a positive link between smoking cannabis and cancer was Zhang et al., (1999), who showed that cannabis users were 2.6 times more likely to suffer from head and neck cancer' does not suggest causality. 68.40.167.60 15:20, 5 September 2006 (UTC)
That is exactly what it does. You need to understand that alot of bad science surrounds the subject of cannabis and this needs to be taken into account. The reference to interactions refers to the fact that the people in the study were on a variety of drugs including tobacco. So far as I have seen only studies that include tobacco smokers seem to show any increase in cancer rates. HighInBC 15:40, 5 September 2006 (UTC)
Again: Why don't you add your evidence to the article instead of removing a relevant, sourced statement? The study states the results need be interpreted with some caution in drawing causal inferences. The statement 'One of the view studies to show a positive link between smoking cannabis and cancer was Zhang et al., (1999), who showed that cannabis users were 2.6 times more likely to suffer from head and neck cancer' does not suggest causality. 68.40.167.60 15:20, 5 September 2006 (UTC)
My point is I don't think it is relevant. Does anyone else have an opinion on this? HighInBC 15:46, 5 September 2006 (UTC)
I would like to point out WP:Reliable_sources#Exceptional_claims_require_exceptional_evidence, which says if a source contradicts other sources it should require exceptional evidence. The studies disclaimer at the end tends to indicate a low confidence, not exceptional evidence. HighInBC 15:49, 5 September 2006 (UTC)
Well, go ahead and closely and skeptically examine the source, but like I said the disclaimer you posted is about inferring causality.
Your study seems to have trouble passing peer review:
[2] directly disputes the study and [3] contradicts it.
As I said, bad methodology, non-reproducable results. HighInBC 15:58, 5 September 2006 (UTC)
Why not include the study, and those reviews, in the article? I am going to add them. —The preceding unsigned comment was added by 68.40.167.60 (talk • contribs).
Why not? Because it has been debunked, that is how science works, one person makes a claim and others review it. It is called peer review, and the citation is merely misinformative. Also re-adding the citation at this point would be a violation of WP:3RR. HighInBC 16:06, 5 September 2006 (UTC)
The article should mention that it has been debunked. This is important and relevant information, which is why you felt the need to post it here. Please add it to the article. I guess you are right about the 3rr rule, I will have to wait until my 24 hrs are up. 68.40.167.60 16:13, 5 September 2006 (UTC)
Even after 240 hours it is not acceptable to use a citation that has failed peer review. I have given you the link to WP:Reliable sources many times now. Also, what goes on the talk page is discussion, the need to post something here does not give it the need to be included inthe article. This is junk science that has failed peer review. If we allowed that then there are studies that show men grow boobs and one joint will kill you, all of which has failed peer review. HighInBC 16:20, 5 September 2006 (UTC)
Perhaps you can create an article called Debunked myths about cannabis for such things, they would be relevent there, but not here. HighInBC 16:21, 5 September 2006 (UTC)
First of all, I checked out your cites here, and I found one study that contradicted Zhang's study, and another study citing that study, does this mean Zhang has been debunked? The 'myth' in question has to do with health issues and the effects of cannabis; I think it is relevant. The statement 'one study reports a correlation between marijuana use and cancer' has not failed peer review, it is agreed upon by those reviewing it and should be in the article. 68.40.167.60 17:01, 5 September 2006 (UTC)
The findings of the study were considered to be invalid due to the methodology used. There are plenty of studies out there that have passed peer review. That statement is misleading. As I said before, there is alot of bad science regarding cannabis and one must take into account the strength of a study. Please look through the talk page archives and you will find a few studies that have been tossed out of this article for similiar reasons. It is standard procedure to remove studies that have been found faulty. HighInBC 17:02, 5 September 2006 (UTC)

[4] simply says 'Zhang and colleagues reported that marijuana use may increase risk of head and neck cancers in a hospital-based case-control study in the United States, with dose-response relations for both frequency and duration of use. However, Rosenblatt and co-workers reported no association between oral cancer and marijuana use in a population-based case-control study.' It says that one study is hospital-based and the other is population-based, but it does not say that the methodology is bad.

[5] also says nothing about methodolody in Zhang's study other than it is hospital-based.

Does the fact that it is hospital-based invalidate its findings? Why? Do you have access to the full text of these articles?

I still don't see why wikipedia can't mention a that a flawed study exists and that it has been refuted. 68.40.167.60 17:39, 5 September 2006 (UTC)

In response to your last question we do mention flawed studies exist, it says at the top of the article:
There is today still a substantial amount of propaganda, junk science, and misinformation about cannabis; both from advocates of cannabis and from its opponents. There are also severe legal and political constraints on cannabis research.
Although there are many conflicting studies involving cannabis, certain physical and mental health effects have been concluded.
This clearly states that not only do bad studies exist, but that they are not mentioned here. HighInBC 18:08, 5 September 2006 (UTC)
Your reading of the first citation is very limited, I will quote the short citation then:
However, there was no assessment of the dose response, and marijuana may have been mixed with tobacco. Parental marijuana use during gestation was associated with increased risks of childhood leukemia, astrocytoma, and rhabdomyosarcoma, but dose-response relations were not assessed. In summary, sufficient studies are not available to adequately evaluate marijuana impact on cancer risk. Several limitations of previous studies include possible underreporting where marijuana use is illegal, small sample sizes, and too few heavy marijuana users in the study sample.
This as a statement that the methodology was flawed. As for mentioning a flawed study, please note the Health issues and the effects of cannabis is a technically oriented article and not as accepting to opinion as a philisophical article such as Arguments for and against drug prohibition. Another point is that you can triple the length of this article if you included studies that failed peer review. It is off topic.
As for the second citation, it points out that statistical findings to not support the experimental findings of the study. HighInBC 17:50, 5 September 2006 (UTC)

(edit conflict, moved down)

The first cite you've (anon) listed here doesn't say the methodology is bad directly, it says that the results were not reproducable. The second one isn't about methodology, it's a contrary study that found different results. The first study linked to by HighInBC, however, also attacks Zhang's methodology and determines that it's inconclusive: "In summary, sufficient studies are not available to adequately evaluate marijuana impact on cancer risk." HighInBC has pretty clearly established here that Zhang's study has not stood up to peer review. siafu 17:57, 5 September 2006 (UTC)

"In summary, sufficient studies are not available..." This does not address Zhang's methodology. What exactly about it was bad? HighInBC, that stuff about dose-response and tobacco is talking about a different study, not Zhang's. It specifically says that Zhang's does take dose-response into effect. 68.40.167.60 20:05, 5 September 2006 (UTC)

It says the findings of the study do not reflect the available information. This makes alot of sense to me, I don't see your point of contention. HighInBC 21:12, 5 September 2006 (UTC)

There is no evidence that Zhang's study was bad other than the one other study that contradicts it. Thus we have one study that says yes, one that says no. What makes one more right than the other? It is obvious to me that both studies should be included in the article. 68.40.167.60 21:41, 5 September 2006 (UTC)

The study was done partially in response to Zhang's, so I bet there is some reason why it is better. Maybe we should look into this. 68.40.167.60 21:49, 5 September 2006 (UTC) edit: toned down language 68.40.167.60 04:06, 6 September 2006 (UTC)

Zhang's sample size is small: 173 with 176 controls. 68.40.167.60 04:55, 6 September 2006 (UTC)

I agree that when we have a small study that says 'yes,' and large studies that say 'no,' we should probably agree with the 'no.' The article should reflect this. However, we can't call Zhang's study 'junk science'; its methodology (other than sample size) has not been disputed. 68.40.167.60 16:02, 6 September 2006 (UTC)

Here[6](originally from here[7]) is another doctor debunking the findings of the study in question. HighInBC 16:38, 6 September 2006 (UTC)
Since "only two had not also smoked cigarettes", all Zhang really found was that cigarettes cause cancer. Note also that "one would conclude from looking at the data that 8.2% of non-cigarette smoking, non-pot smoking controls got cancer while only 7.1% of pot smokers that did not smoke tobacco got cancer". I have read many studies about cancer and cannabis, and the pattern is clear that cannabis supresses cancer. Anarchist42 17:27, 6 September 2006 (UTC)
68, I really hope we can put this baby to bed now. The study is faulty. HighInBC 18:07, 6 September 2006 (UTC)

[8] also says, "A valid conclusion that may be drawn from the data in the study is that cigarette smoking promotes squamous cell neck cancer and that the chance of getting the disease increases if marijuana is also smoked."

Zhang's study simply says that there is a correlation between marijuana smoking and cancer, and claims to control for tobacco use. From Zhang: "Controlling for age, sex, race, education, alcohol consumption, pack-years of cigarette smoking, and passive smoking, the risk of squamous cell carcinoma of the head and neck was increased with marijuana use [odds ratio (OR) comparing ever with never users, 2.6; 95% confidence interval (CI), 1.1-6.6]."

Note that [9] says, "Of the 173 squamous cell neck patients, only two had not also smoked cigarettes." There were also 176 control subjects. 68.40.167.60 00:06, 7 September 2006 (UTC)

Also, [10] is quite POV and seems more likely to be biased "junk science," or simply rhetoric, than Zhang. 68.40.167.60 00:11, 7 September 2006 (UTC)

Control subects are of no value unless there is something to compare it to. The fact that only 2 of the cannabis smokers did not also smoke tobacco is enough to discredit the study. I made it very clear that while the whole article is on [11], that is originated from [12]. You seem determined to defend anything that makes drugs look bad and question anything that makes drugs look good. Your bias has become more and more evident over time. This may be the result of more than one person sharing your IP, I cannot tell as you don't have a username. But if all of the edits by your IP are from the same person the a very strong POV agenda seems to be evident. HighInBC 00:15, 7 September 2006 (UTC)

Now that I think about it, I'm not sure if the fact that there were also 176 controls really proves anything in this case and I wish I hadn't said it.68.40.167.60 00:29, 7 September 2006 (UTC)

Zhang does claim to control for tobacco use though...

How about if we add something like:

A valid conclusion that may be drawn from the data in the study is that cigarette smoking promotes squamous cell neck cancer and that the chance of getting the disease increases if marijuana is also smoked.

However, if anything, marijuana smoking alone seems to reduce the odds of getting it.

to the article?

68.40.167.60 00:32, 7 September 2006 (UTC)

The inclusion of the citation has been clearly opposed by the consensus of the editors here. The reasons for opposing range from critism from the scientific communtity, bad methodology including the vast majority of test subjects smoking tobacco, and a small sample group. You are the only person still supporting it. Per WP:Consensus this citation should not be included. . HighInBC 01:33, 7 September 2006 (UTC)

[edit] Can't comprehend this sentence...

From the end of the section on reproductive effects...

The absence of any differences between the exposed on nonexposed groups in the early neonatal period suggest that the better scores of exposed neonates at 1 month are traceable to the cultural positioning and social and economic characteristics of mothers using marijuana that select for the use of marijuana but also promote neonatal development.

This sentence is incomprehensible to me, but I don't know how to correct its wording.204.126.229.2 18:41, 13 September 2006 (UTC)

It is talking about a flaw in the methodology where the results are skewed based on the social positions of the subjects. Makes sense to me. HighInBC 19:02, 13 September 2006 (UTC)

Correlation studies: It says in the paragraph that schizophrenia is a mood disorder, but I thought that it was considered a thought disorder. In fact, if there is a mood disorder along with schizophrenia like symproms, the disorder is called schizoaffective.

[edit] Trichome image

The article currently includes Image:Trichome-close-up.jpg.

The image was deleted for WP:PUI.

I had nothing to do with the deletion but do know that the source of the image is http://www.hempreport.com/issues/17/malbody17.html and use here may be WP:COPYVIO

It is not clear how the image is related to the subject of this article, because:

  • the article does not currently discuss trichomes or cannabinoid biosynthesis
  • these topics are not within the scope of Health issues and the effects of cannabis

The image would be useful to illustrate a comprehensive discussion of cannabinoid biosynthesis, but none of the Category:Cannabis articles currently include such a discussion. The image might also be useful at Trichome, as well as at Hashish, Bubble hash, Kief, or other cannabis articles that link to Trichome.

I have reverted the article to the previous version without the image until the copyright status can be cleared up.

Chondrite 19:52, 28 September 2006 (UTC)

[edit] New info

Can anyone find the study this article is refering to[13]? HighInBC 15:52, 7 October 2006 (UTC)

The findings appear in the Aug. 9 online edition of the journal Molecular Pharmaceutics, a publication of the American Chemical Society: Abstract & Full text. (I'm at work right now so I can read the full-text because of my job's institutional subscription. If you can't read it, let me know and I can download a copy and host it somewhere else.) --Howrealisreal 15:08, 9 October 2006 (UTC)

Thank you, I will read through that later and add what I can to the article. HighInBC 15:52, 9 October 2006 (UTC)

I have added my interpretation of the study to the article[14] please let me know what you think and polish it up as needed. HighInBC 15:10, 15 October 2006 (UTC)

[edit] Citations

I have gone through several citations and modified the article to more accuratly represent them. Please give constructive critisism if needed. HighInBC 16:34, 15 October 2006 (UTC)

[edit] "Cannabis has different and fewer effects on the lung": Does it really?

First of all I have to admit that this article is quite detailed and well referenced. It shows there has been a lot of effort put into it. I do, however, have an issue with one section of it. In regards to Health_issues_and_the_effects_of_cannabis#Different_and_fewer_risks_than_tobacco, I am unsure of some of the assertions. First, there is no reference for the positions or variation of the "concentration" of tobacco/cannabis (I assume it means smoke) in the lung, but I shall treat this as being correct. Secondly, the reference used for the emphysema/COPD claim only discusses FEV1, while I would have liked to see other measures of COPD disease such as FEV1/FVC, FEF25-75, and PEF. Unfortunately I cannot get the article online, so this particular issue may be left unanswered. Third, if we do presume that cannabis smoke does deposit significantly in the upper airway (and there is inflammation; this appears to be correct), the FEV1 (and therefore the reference for COPD incidence) becomes less useful. Central airway damage would give you a disease profile more similar (but not identical) to bronchiectasis, which can easily hide the lung function indications of COPD. If you really want to claim that cannabis does not cause various types of lung disease, the only way to do it would be via the clinical diagnosis: high-resolution CT scans. Until a comprehensive paper has carried this out (along with a full range of lung function tests), I dispute that this single reference justifies the claim can be made (especially if inflammation does occur in the central airways). Of course, since it's peer reviewed, it could be put into the article, but perhaps the mention of HR-CT scans would help clarify whether this is actually true. And finally, I wrote on a parent talk page, I believe that using the word "fewer" is potentially misleading. Is fewer a reference to total incidence of lung disease? Or the sum of the types of disease? Or the severity of disease? My interpretation of the article is that because COPD *may* not occur (and a few papers also suggest cancer rates are different), that the number of lung diseases, or its incidence is lower? More concerning for me is that the general public can easily mistake "fewer" as meaning "safer"; something that I believe must either be clarified as not necessarily being correct, or the word "fewer" should be changed/removed. When we are basing these claims off a missing reference (I have no immediate reason to assume it to be false) and one paper (especially with the issues discussed above), I'm unsure how strongly Wikipedia can assert that COPD does not appear to exist. Perhaps pointing out that the way to truly determine this is via high-resolution CT scans? On a different note: the link to radioactive tobacco does not work without access to the library password, you'll have to find another source for the reference.Volantares 05:58, 30 November 2006 (UTC)

These are good comments and I encourage you to edit the article appropriately. Regarding the radioactivity link, I've removed the URL to a subscription site, but left the reference because there's no requirement that sources be available online. I'm aware that some researchers have claimed that radioactivity is a major cause of cancer in tobacco smokers, and that this is related to contamination of fertilizers commonly used in tobacco cultivation. Additional info is given in Tobacco smoking#Health risks of smoking, although that article cites the same source as this one, with one additional (poor) source. If I recall correctly, this subject has been debated in the letters section of NEJM, although I am not personally aware of any peer-reviewed papers on the subject. I will try to dig up some additional information. Chondrite 06:42, 30 November 2006 (UTC)
Does it really? Good question. However, the threshold for inclusion here is verifiabality, not truth. So, the difficulties in finding a test group of people that smoke cannabis and not tobbacco(yo!) result in a lack of data to build the article from.
A sentance could be added stating something along the lines of These studies have all been limited by a lack of test subjects that smoke cannabis but not tobbacco. But only once a citation is found to support this. Of course, my example sentance could misrepresent the reality of the situation, which is why a citation is needed.
Thanks for helping us, you seem very intellegent and we need good researchers for this article as contentious subjects need extra research. HighInBC (Need help? Ask me) 14:54, 30 November 2006 (UTC)
If our criteria for inclusion is that a fact must be verified, you will have to exclude any information that does not have the same result from two different research groups. This is arguably too stringent; I think it CAN be justifiable to include unusual results, but a lot of care must be taken not to put too much weight on it, and particular attention must be paid to the methods used to get such data.
All that said, I'd recommend you read my comment below this one in regards to "cannabis but not tobacco smokers". You are correct in saying that such a group is very rare. I will leave you to read that post for comments. Our ability to conclude facts is weakened, but not destroyed, provided the results are different between groups.
Hi. I concur these are great comments, and a fresh perspective/contributer to this article is definitely valuable. I agree that maybe a better section heading, one that avoids using words like "fewer risks" for the smoking section is a good point. It may be true in regard to tobacco radioactivity, a major proponent of that viewpoint was former U.S. Surgeon General C. Everett Koop who first popularized the Polonium-210 connection, but perhaps not proven yet across the board. On a side note, I happen to work for a medical college that has online subscriptions to almost every scientific journal. If there's any papers that you'd like me to provide, just drop me a note and I'd be more than happy to try and dig them up. --Howrealisreal 15:17, 1 December 2006 (UTC)
I removed the bit about radioactivity because it appears to be undue weight. "Levels of polonium-210 in tobacco smoke are not believed to be great enough to significantly impact lung cancer in smokers" [15], and "It has been estimated that about 1% of the lung cancer risk associated with cigarette smoking could be ascribed to polonium-210. "[16] -- Chondrite 07:38, 5 December 2006 (UTC)
The source that was in the article before [17], that was commented out, states: "Lung cancer has been induced in test animals using less than one-fifth the Po exposure experienced by a two-pack-a-day smoker during 25 years of smoking. It has been suggested that Po accounts for many, if not all, cigarette smoke-induced lung cancers." But the point is not specifically with Po, it's the fact that there are many more additives in tobacco that have been connected with cancer than in cannabis. There's also lead 210, nitrosamines, benzopyrene, and even nicotine is thought to exacerbate cancer by "reacting unfavorably with microsomal enzymes in the liver." --Howrealisreal 15:45, 5 December 2006 (UTC)

[edit] The problem with Tobacco

I don't know how much this is discussed, but I thought I'd clarify people's understanding of smoker research. It has been my experience that often a little bit of lee-way is granted when it comes to the issue of tobacco smoke, because it would be practically impossible to do the studies otherwise. The usual control system would involve recruiting people who have had very low tobacco exposure (i.e. less than a defined (and low) number of pack years, 1 pack year = 1 pack/day/year or an equivalent factor thereof), and to then presume that any tobacco related damage would be very limited or zero. Certainly that damage could be easily quantified by HR-CT scans and/or other measurements. While cannabis alone would be a better population to compare against tobacco (along with both), that population almost DO NOT EXIST. The implication is that we must presume that the two drugs added together have an additive or multiplative effect. In fact, this design decreases the sensitivity of proving cannabis is damaging, i.e. if the effects are not cummulative, false negatives could potentially occur. Oh, and you can be assured that the whole thing about people who use "tobacco/cannabis" combinations are much more easily removed or controlled for, so that complication is not a major issue in comprehensive scientific articles.Volantares 05:58, 30 November 2006 (UTC)

I volunteer for this study(as long as I do not have to smoke tobacco). HighInBC (Need help? Ask me) 15:29, 1 December 2006 (UTC)


[edit] Recent discovery that it may not be all bad

I found an article on a website that describes the 10 top bad things that are good for you, one of them is on marijuana:

It's medicinal, we swear! Marijuana, often associated with memory loss, is ironically now being hyped as a way to stave off the ultimate form of memory loss—Alzheimer's. Recent studies on mice suggest that anti-inflammatories found in the drug prevent the clumping of brain proteins, one major cause of the disease. So when should you start preventative therapy? We suggest waiting for the human studies to wrap up.

[Top Tend Things that are Bad for you : Marijuana]

I don't have the time or resources to check this, but if this is correct the page needs editing. --GBobly 07:28, 4 December 2006 (UTC)

So does this mean that you are able to keep the potential to create memories, but impair your ability to actually develop them? A little more seriously, it will be important to point out whether the study investigated marijuana smoke, or THC. That difference is important in terms of cost/benefits, and medical merit. Volantares 14:27, 4 December 2006 (UTC)
We already mention that it is a potential treatment of Alzheimer’s at the bottom of Health_issues_and_the_effects_of_cannabis#Physiological_effects. I added that part when the study came out. HighInBC (Need help? Ask me) 16:33, 4 December 2006 (UTC)

[edit] Gateway hypothesis

The following statement was added to the article: "A 12-year study performed by the University of Pittsburgh and published on December 4, 2006 appears disprove this hypothesis, however.", citing [18]. The abstract for the actual paper is here. I haven't read the full text but the abstract states that "The authors investigated whether the transition from licit drug use to marijuana use is determined by particular risk factors...", and describes the "'gateway sequence' (illicit drug use following licit drugs)". This is not the same as the gateway hypothesis described in the article: "The gateway drug hypothesis asserts that the use of cannabis may ultimately lead to the use of harder drugs." The abstract says that a significant minority of subjects who used cannabis did not follow the gateway sequence (licit drug use followed by illicit drugs), strongly implying that the majority did in fact follow the gateway sequence. So regardless of what the cited news source stated, the abstract of the actual paper: (a) is not relevant to the hypothesis described in the article, and (b) does not support the conclusion advanced in the article. Accordingly, I have removed the statement from the article. The paper is definitely useful as a source if someone wants to write a section on "risk factors for cannabis use". Chondrite 08:38, 7 December 2006 (UTC)

Just reading the news article flags it as being poor reporting. The title of the article has nothing to do with the results actually discussed in the article (this would suggest that those editors probably shouldn't have a job), and the research itself sounds like they were looking for something and found a result for something else. Given the title of the article however, that inconsistency may stem from the news article, not the research. Volantares 13:34, 9 December 2006 (UTC)
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