I said: Read this news report. Then answer a simple question: who > were the subjects of this alarming study? > --------------------------------- > Cannabis Damages Young Brains More Than Originally > Thought, Study Finds
On 24 Dec 2009 at 13:47, Gerald Peterson wrote: > Is the objection to the sweeping generalities in the piece? Is it to the > emotionalism in the news notice? > <snip> Is it that a rat model is not appropriate to answer questions about > cannabis effects? Is the rat > model not at all relevant to human teen brains? It seems that my outrage has been met with puzzlement. I wasn't disputing the importance of animal research, or its relevance for understanding the human brain. I fully support animal research for advancing neuroscience. What I do not support is omitting essential information from a press release and from news article based on that release. The significant information was the word "rat". It seems to me there was likely a deliberate attempt to prevent the reader from learning that the study was carried out in rats, and instead to encourage the conclusion that humans were studied. This was done by using terms such as "adolescent", "teens", and even "Canadian teenagers", all of which (unless some rats have taken to wearing baggy pants, dissing their parents, and listening to hip-hop) invariably makes us think of not-fully-grown humans. I never heard a rat called a "teenager" before this study, Canadian or not. Why they did it is obvious. Studies demonstrating the dangers of cannabis for teenagers are sexy; such studies for rats, not so much. If you want publicity, you go with what is sexy, and hide what can impair it. It's also wrong. Rat studies are important. But it's a truism that rats are not people, and we cannot simply assert their interchangeability, at least not without further evidence. At a minimum, I would have expected responsible researchers to say something like this, "While this study was carried out in rats, future research may lead to the discovery of similar brain changes in teenagers". But if they did that, everyone, including journalists, would say "ho-hum". Because we've had more than a few generations of dire warnings about the toxic and brain-damaging properties of pot, none of which have been supported by credible evidence. One more rat study wouldn't do it for most people. Moreover, if these researchers were so determined to show that cannabis is harmful to humans, why weren't they studying humans in the first place? Yes, we have to use rats to study changes in neurochemicals in the brain, because teenagers won't lend us their brains for the purpose. But the neurochemical changes---> depression hypothesis is in trouble, and jumping from neurochemical changes in the rat brain to human depression is a leap as great as the best of Evel Knievel's. Note that the behavioural measures in this study were such things as "forced swim" and "sucrose preference" for depression, and "novelty-suppressed feeding test" for anxiety. When was the last time we diagnosed depression and anxiety in teenagers with those kind of tests? OK, rant ends. I repeat the offending news report below so you can compare it with the above. As you read it, remember, they're really talking about rats for their findings. Stephen > > ScienceDaily (Dec. 20, 2009) - Canadian teenagers are > among the largest consumers of cannabis worldwide. The > damaging effects of this illicit drug on young brains are worse > than originally thought, according to new research by Dr. > Gabriella Gobbi, a psychiatric researcher from the Research > Institute of the McGill University Health Centre. The new study, > published in Neurobiology of Disease, suggests that daily > consumption of cannabis in teens can cause depression and > anxiety, and have an irreversible long-term effect on the brain. > > "We wanted to know what happens in the brains of teenagers > when they use cannabis and whether they are more susceptible > to its neurological effects than adults," explained Dr. Gobbi, who > is also a professor at McGill University. Her study points to an > apparent action of cannabis on two important compounds in the > brain -- serotonin and norepinephrine -- which are involved in > the regulation of neurological functions such as mood control > and anxiety. > > "Teenagers who are exposed to cannabis have decreased > serotonin transmission, which leads to mood disorders, as well > as increased norepinephrine transmission, which leads to > greater long-term susceptibility to stress," Dr. Gobbi stated. > > Previous epidemiological studies have shown how cannabis > consumption can affect behaviour in some teenagers. "Our > study is one of the first to focus on the neurobiological > mechanisms at the root of this influence of cannabis on > depression and anxiety in adolescents," confirmed Dr. Gobbi. It > is also the first study to demonstrate that cannabis consumption > causes more serious damage during adolescence than > adulthood. > > http://www.sciencedaily.com/releases/2009/12/091217115834.h > tm or http://tinyurl.com/yc99kal ----------------------------------------------------------------- Stephen L. Black, Ph.D. Professor of Psychology, Emeritus Bishop's University e-mail: sbl...@ubishops.ca 2600 College St. Sherbrooke QC J1M 1Z7 Canada ----------------------------------------------------------------------- --- To make changes to your subscription contact: Bill Southerly (bsouthe...@frostburg.edu)
