Talk:Long-term effects of cannabis

Lung cancer 2

Hi, I'm wondering why the main part of 'Lung cancer' takes the BLF's 2012 report when some experts like David Nutt think [1] it's just scaremongering. While the largest and longest [2] study [3] isn't mentioned at all.Popelin (talk) 09:19, 25 May 2014 (UTC)

It's because we have agreed that we don't use a blog or a single study to refute a good quality secondary source. It's explained in detail at WP:MEDRS. --RexxS (talk) 20:57, 25 May 2014 (UTC)

Is this a primary or secondary ("data were pooled from 6 case-control studies") source ? Thanks. Popelin (talk) 19:53, 24 June 2014 (UTC)

It's a secondary source (indexed by Pubmed as PMID 24947688). Zhang et al took six studies to do their pooled analysis. I can't tell whether it's the highest quality of source, because it's not clear how the authors selected the six studies. It doesn't seem to have reached conclusions about much though. --RexxS (talk) 00:36, 1 July 2014 (UTC)

I've just realised: this is a reprint with an expanded analysis of http://cancerres.aacrjournals.org/cgi/content/meeting_abstract/73/8_MeetingAbstracts/3633 which is already used as a reference (current number 27) for the third paragraph of the Lung section. --RexxS (talk) 00:53, 1 July 2014 (UTC)

Neutrality

I think this article represents the negative health effects of cannabis very well, though it makes little to no mention of the positive effects observed in research. There are lots of studies available on the matter, here are a few that I found within 10 minutes:

Cancer:

Inhibition of colon carcinogenesis by a standardized Cannabis sativa extract with high content of cannabidiol.

Cannabis extract treatment for terminal acute lymphoblastic leukemia with a Philadelphia chromosome mutation.

Cannabidiolic acid, a major cannabinoid in fiber-type cannabis, is an inhibitor of MDA-MB-231 breast cancer cell migration.

Non-THC cannabinoids inhibit prostate carcinoma growth in vitro and in vivo: pro-apoptotic effects and underlying mechanisms.

Cannabinoids: a new hope for breast cancer therapy?

Towards the use of non-psychoactive cannabinoids for prostate cancer.

Epilepsy:

Cannabidiol exerts anti-convulsant effects in animal models of temporal lobe and partial seizures.

Marijuana: an effective antiepileptic treatment in partial epilepsy? A case report and review of the literature.

Report of a parent survey of cannabidiol-enriched cannabis use in pediatric treatment-resistant epilepsy.

Multiple Sclerosis (MS):

Cannabidiol provides long-lasting protection against the deleterious effects of inflammation in a viral model of multiple sclerosis: a role for A2A receptors.

What place for ▾ cannabis extract in MS?

Treatment of spasticity in multiple sclerosis: new perspectives regarding the use of cannabinoids

Parkinson's Disease:

The multiplicity of action of cannabinoids: implications for treating neurodegeneration.

Survey on cannabis use in Parkinson's disease: subjective improvement of motor symptoms.

Cannabis in movement disorders.

Depression:

Study: cannabis a double-edged sword (This study found a pronounced anti-depressant effect at low doses, though large doses worsened it)

Antidepressant-like effect of Δ9-tetrahydrocannabinol and other cannabinoids isolated from Cannabis sativa L

I think it should also be noted that many of the studies indicating a carcinogenic or otherwise deletrious effect are in regards to smoked cannabis (and often cannabis smoked via the more common means instead of vaporization, which may produce less carcinogenic byproducts than cannabis smoked via flame-heating). I think this point should be emphasized, as it is already well established that inhalation of smoke released from combustion is often toxic, so it's not unreasonable to assume that a large portion or all of the organ damage associated with cannabis use might be from it's use via combustion instead of oral or vaporization. Further research is definitely justified.

I'm not disputing the negative effects outlined in this article, as they're well founded. I do believe the article needs much more coverage of the investigated positive effects, as well as clarifying that it is not yet clarified if the method of consumption affects the toxicity of regular cannabis use. LiamSP (talk) 02:46, 24 February 2014 (UTC)

There are long-term positive effects? Any reliable (i.e. WP:MEDRS) sources for that? Alexbrn ^{talk|contribs|COI} 05:21, 24 February 2014 (UTC)

@LiamSP: Aside from the point that this article is concerned with long-term effects of cannabis, not Medical cannabis, all of the reports you've listed are primary studies. It's worth reviewing the advice given in WP:MEDRS to understand why we strongly prefer to use secondary sources. Our article has 12 sources marked as "review" or "meta-analysis" and they seem to me to present a fairly consistent picture of the long-term effects of cannabis - which I hope our article reflects reasonably accurately - even if they don't have much positive to report. If you know of any equally-good-quality recent secondary sources that deal with other aspects of the long-term effects of cannabis, then please let's use them. I've had no luck yet in finding the positive long-term effects of cannabis in a secondary source and I've put a lot more time than 10 minutes into searching. --RexxS (talk) 15:59, 24 February 2014 (UTC)

Merge two section

I think the sections title 'Lung' and 'Respiratory Effects' should be merged. I realize the lung bit is under cancer but the repisratory effects section seems to add little that couldn't be included in the Lung Section. ACanadianToker (talk) 03:49, 28 May 2014 (UTC)

One section is about lung cancer which is different than respirtory effects so IMO they should be kept seperate. Doc James (talk · contribs · email) (if I write on your page reply on mine) 10:50, 28 May 2014 (UTC)

British Lung Association report

There is absolutely nothing in the sources here to support the use of the word "controversial" in describing the BLA report:

• "The impact of cannabis on your lungs". British Lung Association. June 2012. Retrieved 2013-01-09.

It is not unusual for supporters of cannabis use to criticise such reports, but the BLA 2012 report is a good MEDRS-compliant source and its criticism is undue for this article unless that criticism meets the same standards. It is not the place of Wikipedia to white-wash the effects of cannabis, but to report as neutrally as possible the conclusions of the best sources. We already have Gordon (2013), BLA (2012) and Zhang (2013) that represent the range of conclusions in the best sources. If there are other equally good sources that offer very different perspectives, then let's discuss them. --RexxS (talk) 18:14, 16 June 2014 (UTC)

The claim "the risk of developing lung cancer is nearly 20 times higher from smoking typical cannabis cigarettes" is not supported by their sources, or them in fact. Even the study on which it was based did not come to this conclusion and this study was refuted in the very same journal it was published. The BLF did not suggest that the cannabis risk was 20 times greater, they were merely talking about that one study. The BLF also states "However, studies in human populations have yielded conflicting evidence on the subject: some suggest there is a link between smoking cannabis and lung cancer while others don’t. In fact they sum up that section of the report with "Further research is needed to confirm these findings and to explain why smoking a cannabis cigarette MIGHT pose a greater risk than smoking a tobacco cigarette. Identifying the mechanisms by which the components of cannabis smoke MAY cause lung cancer is also crucial". — Preceding unsigned comment added by Psyden (talk • contribs) 21:37, 16 June 2014 (UTC)

From "The impact of cannabis on your lungs":

• A rigorous case-control study by Aldington and colleagues in 2008 made significant progress in showing that the link exists. The authors analysed the smoking habits of people diagnosed with lung cancer and a control group without lung cancer. Their major finding was that smoking cannabis increases the risk of developing lung cancer in young adults. The study also suggests that smoking one cannabis cigarette a day for one year increases the risk of lung cancer by 8 per cent. Importantly, researchers took variables including tobacco smoking into account when calculating this figure. By way of comparison, the same study suggests that smoking one pack of tobacco cigarettes (20 cigarettes) a day for one year increased the risk of lung cancer by 7 per cent. This suggests that smoking just one cannabis cigarette increases the risk of developing lung cancer by a similar amount as smoking 20 tobacco cigarettes. The study also concluded that 5 per cent of lung cancers in those aged 55 or under may be caused by smoking cannabis.

The source clearly supports our text. We don't do amateur analysis of secondary sources to try to reach other conclusions; we summarise neutrally what the secondary source says. If you've got equally good sources that offer criticism of the source used, let's see them (and I don't mean a blog from a dissenter with an axe to grind). Now if you think that our summary of "The impact of cannabis on your lungs" in the Lung section doesn't represent neutrally what that report says, then feel free to propose different text, but their own first-page summary is quite explicit:

• Current evidence shows that smoking cannabis is hazardous to our lungs. We know far less about the effects of cannabis smoke than the impact of tobacco smoke. However, there is evidence that cannabis smoking is linked to many adverse effects, including: chronic coughing; wheezing; sputum (phlegm) production; tuberculosis; legionnaires’ disease; aspergillosis; acute bronchitis; airway obstruction; pneumothorax, and lung cancer.

Your choice of quote and inaccurate emphasis on the words 'might' and 'may' COULD be construed as cherry-picking an unintended meaning from what is a common disclaimer suggesting further research would make clearer the conclusions. --RexxS (talk) 11:10, 17 June 2014 (UTC)

It does not at all support our text. Our text implies that the BLF concluded cannabis smoking has a 20 times greater risk of lung cancer when clearly they did not. Again, they were simply discussing one study, not concluding anything. The sentence in question needs to be removed or reworded. "A 2012 literature review by the British Lung Foundation found evidence that smoking cannabis is linked to lung cancer." would be a more accurate representation of this aspect of their report. Psyden (talk) 01:18, 18 June 2014 (UTC)

You mean that you feel:

• This suggests that smoking just one cannabis cigarette increases the risk of developing lung cancer by a similar amount as smoking 20 tobacco cigarettes. - source

does not support:

• A 2012 literature review by the British Lung Foundation suggested that the risk of developing lung cancer is nearly 20 times higher from smoking typical cannabis cigarettes than from smoking tobacco cigarettes - our text

It looks to me like it does support the text. BLF equates 1 cannabis cigarette with the same carcinogenic risk potential as 20 tobacco cigarettes. However, concentrating on that one part of the report could be seen as undue, so I have some sympathy with your suggested re-write. Wouldn't you say though, that your "linked to lung cancer" is a rather anaemic summary of "linked to many adverse effects, including: chronic coughing; wheezing; sputum (phlegm) production; tuberculosis; legionnaires’ disease; aspergillosis; acute bronchitis; airway obstruction; pneumothorax, and lung cancer"? How about replacing the sentence

• "A 2012 literature review by the British Lung Foundation suggested that the risk of developing lung cancer is nearly 20 times higher from smoking typical cannabis cigarettes than from smoking tobacco cigarettes, due to deeper, longer inhalation and the lack of filters."[ref]

with:

• "A 2012 literature review by the British Lung Foundation concluded that cannabis smoking was linked to many adverse effects, including bronchitis and lung cancer."[ref]

I suggest those two examples of adverse effects as I suspect that smoking almost anything is likely to be linked to coughing, wheezing, sputum, etc. but evidence of links to bronchitis and lung cancer is a rather more significant finding. What do you think? --RexxS (talk) 00:30, 19 June 2014 (UTC)

Yes. In their sentence:

• This suggests that smoking just one cannabis cigarette increases the risk of developing lung cancer by a similar amount as smoking 20 tobacco cigarettes.

the word "this" refers to that one study (Aldington and colleagues), it is not the BLF's conclusion. So I feel your suggestion: "A 2012 literature review by the British Lung Foundation concluded that cannabis smoking was linked to many adverse effects, including bronchitis and lung cancer.", would better represent their findings.

clarification on edit, re smoking it

The study that talks about the possible risk of lung and prostate cancer is in the context of smoking cannabis--not consuming it as food, or drink. The links to cancers are from the smoke, and the way the article reads is currently misleading on this point. I tried to edit to correct his, but it was reverted. 67.180.77.106 (talk) 02:40, 17 June 2014 (UTC)

The study supporting the text that you altered is

• Gordon AJ, Conley JW, Gordon JM (December 2013). "Medical consequences of marijuana use: a review of current literature". Curr Psychiatry Rep (Review). 15 (12): 419. doi:10.1007/s11920-013-0419-7. PMID 24234874.{{cite journal}}: CS1 maint: multiple names: authors list (link)

You are completely wrong to assume that the review only considered the context of smoking cannabis, as a glance at the 127 references in that paper will show you. --RexxS (talk) 10:37, 17 June 2014 (UTC)

I read the review but I saw nothing about cannabis causing lung or prostate cancer from consuming it as a vegetable or juice drink, or even extracted oil. All the studies I've seen show that its protective against cancer. The only possible link was in the context of smoking as all combustion produces carcinogens. If I am wrong, then can you please point out where exactly does it say that edibles are also linked to cancer? I'd be very surprised given my knowledge on the subject. As it stands leaving this out, makes it misleading. 67.180.77.106 (talk) 22:34, 4 July 2014 (UTC)

"We surveyed the peer-reviewed medical literature from 1998 to 2013 of studies assessing the association of marijuana use and physical diseases. We conclude that healthcare providers should be cognizant that the existing literature suggests that marijuana use can cause physical harm." I can see where it states "we surveyed ... studies assessing the association of marijuana use and physical diseases" but I can't see anywhere that says "but only the ones where cannabis was smoked". Did you look at the list of studies that Gordon et al examined? Are you trying to claim that those sources were all only concerned with smoking cannabis? It's abundantly clear that Gordon's review examined cannabis use in all its forms, not just from smoking. I'm sorry that its conclusions don't fit your view of cannabis use, but that's what the literature says. Have a read of WP:MEDRS and see that we use secondary reviews to analyse primary studies, rather than relying on anonymous editors drawing conclusions from their personal experiences. --RexxS (talk) 23:48, 4 July 2014 (UTC)

No need to be sorry since we are humans and can interpret the rules in the spirit of the rules: to write a truthful and accurate Encyclopedia. Truth matters, right? It's simply not true that there are any studies which link consuming cannabis as an edible being to causing lung or prostate cancer. Yet, this is what the current wording, implies. Thus it's misleading. I have studied the issue and reviewed the literature: the only such associations that exist to date pertain to smoking only. If that is not true, then please cite a study. Again, does the truth matter? I think so. So we should apply the rules in a way that serves what the evidence shows. My view of Cannabis IS based on what the literature does say. We should write in a clear way that elucidates this literature, instead of obfuscating it. The rules can be used either way. I'm for the former, which is the intelligent, intended, purpose of this, rule, i.e. to tell the truth--not hide behind misleading wordings that falsely imply that non-smoking cannabis consumption is linked to cancer when opposite is the truth of the matter. 67.180.77.106 (talk) 05:04, 13 July 2014 (UTC)

You are repeatedly saying that the studies do not specifically say that one specific intake causes two specific cancers. Then you say your "view of Cannabis IS based on what the literature does say." In this particular case, you are stating what you believe the literature does NOT say. Instead, we are focused on what it does say. For example, your most recent edit to the article indicated that a review article was discussing exposure to marijuana "smoke". However, the article discusses exposure to marijuana. While you are focused here on two forms of cancer, the article in question associates marijuana exposure with "diseases of the liver (particularly with co-existing hepatitis C), lungs, heart, and vasculature". - SummerPhD (talk) 17:20, 13 July 2014 (UTC)

You are correct, however my original point still stands, untouched. Let me clarify. When I said my view is based on what the literature says, I was not only speaking of this one source--but looking at all the literature for years. You are right this particular study is does not specify form of intake. That is why its a bad study that is conflating smoking (which everyone knows is bad) with the herb itself causing cancer. As editors, its our duty to report the best studies--not misleading ones. Or, if not, then a point of clarification should be made about this weakness, and this should be found and cited--if this study is to be used. Currently the way this is used, falls short of the purpose of building an encyclopedia, which is to increase knowledge. Otherwise, we lose sight of the forest for the trees. 24.5.69.164 (talk) 22:40, 15 July 2014 (UTC)

New review

This 2013 review contrasts with Gordon and the BLA's conclusions about the correlation between cannabis and lung cancer. It reads "no clear link to chronic obstructive pulmonary disease has been established". Do you think it should be mentioned in the article?--MarkyRamone92 (talk) 16:37, 30 June 2014 (UTC)

Dr. Donald Tashkin is an expert who specializes the field of lung disease. The findings in his review should be mentioned. Psyden (talk) 19:12, 30 June 2014 (UTC)

Looks like a respectable expert opinion to me. I don't think it says anything about lung cancer that we don't already have cited to http://cancerres.aacrjournals.org/cgi/content/meeting_abstract/73/8_MeetingAbstracts/3633 although it would probably be useful in expanding the opening sentence in the Respiratory effects to point up Taskin's conclusion about COPD. --RexxS (talk) 00:47, 1 July 2014 (UTC)

You are right, Tashkin's findings are essentially similar to those by the International Lung Cancer Consortium regarding lung cancer; however, I think that the sentence "no clear link to chronic obstructive pulmonary disease has been established" adds something to the article, as there is no mention of the COPD in it.--MarkyRamone92 (talk) 07:03, 1 July 2014 (UTC)

I've expanded the first sentence of Respiratory effects to mention COPD and attributed Tashkin. --RexxS (talk) 14:05, 1 July 2014 (UTC)