The story describes one study of about 400 men who were followed from their teens in the late 1980s until 2010. The researchers found no increased risk of asthma, depression, lung cancer or mental illness, which the story seems to accept as a big reassurance. We felt the story did not squarely address the study limitations as described by the authors themselves in the paper. Instead, the “surprising news” came in a single-source story, lifting quotes from a news release, without any independent perspective or adequate context.
Millions of individuals, of all ages, are making current decisions about medical and recreational marijuana use every day. Medical research on the health impacts of that exposure matter for each person and for society as a whole. This story over-valued the conclusion of a single small study based on a sample of only young men. Yes, the study results were interesting and indeed add to a body of knowledge about the use of marijuana by adolescents but it is by no means definitive. Suggesting, “it’s all good” is a misleading leap based on this one limited study.
We’ll rule this Not Applicable. The story didn’t discuss costs, and we acknowledge it would be difficult to pin down marijuana costs from different sources – from the time period in question in the analysis – or today.
Although the story is about research examining harms we think that a brief line or two about the reasons for marijuana use would have been informative. Especially when the author is allowed to say that he wanted to “help inform the debate about legalization of marijuana.” Debates involve tradeoffs of benefits and harms and we heard only one side of it in this story (and incompletely at that).
The story provides a list of the potential harms associated with marijuana use but it over-emphasizes the importance of this relatively small study in downplaying them – calling it “surprising news” that is “all good” in the headline. And the second sentence says the study “should alleviate some of the worst fears.” That is too big a leap.
The story tried to describe the context of previous studies on marijuana but used this language “other studies in the past that seemed to allude to marijuana use and later development of psychotic symptoms such as delusions or hallucinations.” As readers, we want to ask – did previous studies conclude there were risks? How can a study “seem to allude?”
A recent review (N Engl J Med 2014; 370:2219-222) cited 69 publications examining the potential harms of marijuana use by the general population. This one study is simply an addition to the growing body of evidence.
The story provides several hints into the study design. We are told how many subjects were enrolled and the duration of the data collection. We are also told that the 408 really represented 4 separate and distinct groups based on usage with the early chronic users highlighted. This latter group was represented by 86 subjects. The implication is that these young men ingested a good deal of marijuana. Usage was not however uniform. The methods of assessing the presence of absence of the harms under study are not provided (of note: 25 of the original subjects died during the study period with 21 deaths listed as homicides) nor are we told about missing data.
The study was conducted only in male teens, so the headline or early sentence should have emphasized the limitation that the “surprising” findings apply only to one gender. This single study relies solely on the reports of the participants and ended in 2010 – based on their reported use of marijuana in the 1980s and 90s. Many observers believe the marijuana sold in the United States has changed dramatically in the past 25 years. Results on exposures from so long ago may not apply to modern marijuana strains for sale.
Here’s how one laboratory representative described the potency change, in a CBS story from earlier this year.
“We’ve seen a big increase in marijuana potency compared to where it was 20 or 30 years ago,” lab founder and director of research Andy LaFrate, Ph.D., said in a video released by ACS. Based on testing in laboratory equipment, “I would say the average potency of marijuana has probably increased by a factor of at least three. We’re looking at average potencies right now of around 20 percent THC.”
THC, or tetrahydrocannabinol, is the psychoactive compound in marijuana that acts on the brain to produce the feeling of being high.
Not applicable in this case. There was not a single disease or condition explored in any detail.
The story badly needed an independent source. It would have been possible and helpful to choose from among many researchers whose work points to potential harm from chronic marijuana exposure. Again, letting the researcher get away with saying – unchallenged- that he wanted to “help inform the debate about legalization of marijuana” in a single source story is problematic.
This is not an applicable category for this story topic. However, it is interesting to consider whether teens who use marijuana are not using alcohol, and whether that may lower their risk of harms from alcohol use.
The story leads with the “widespread availability of marijuana in recent years” – especially “thanks to its legalization in a growing number of states.”
The story suggests that the study highlighted was novel in that it did not find an association between marijuana use in adolescent and harms seen by other researchers. However, the story did little to provide any context to the differences. Since the intent of this criterion is to establish the true novelty of a finding, we judge the story to be unsatisfactory.
The quotes from researcher Bechtold are identical to those in an American Psychological Association news release.
The story euphemistically refers to these comments appearing in “a statement.” Let’s call it what it is: a news release or press release written by public relations people.
Lifting quotes and then not seeking independent perspectives are a double whammy.