SALON: … From Medical Daily, emphasis ours:
The researchers, from the University of California, San Diego and the University of Pittsburgh Medical Center, performed the study on 92 16- to 20-year-olds. The scientists scanned their brains both before and after an 18-month period. Over the course of the 18 months, half of the teens, who already had an extensive track record with alcohol and marijuana, continued their vices as they had before. The other half continued to abstain or drink a minimal amount, like they too had done before the study.
In addition to the brain scans, the study also required a detailed toxicology report and substance use assessment. The teens also were interviewed every six months. Researchers did not check the teens’ cognitive ability, but simply took brain scans.
The researchers found that, after the year and a half was over, kids who had drank five or more alcoholic beverages twice a week had lost white brain matter. That means that they could have impaired memory, attention, and decision-making into adulthood. The teens that smoked marijuana on a regular basis had no such reduction…. (more)
10 drinks a week for teenagers is an awful lot. But somehow the number of marijuana cigarettes used by the teens is obfusicated. Sounds like cherry picking data to me. A 2002 report by the British Lung Foundation estimated that three to four cannabis cigarettes a day were associated with the same amount of damage to the lungs as 20 or more tobacco cigarettes a day. The study mentioned no lung damage caused by alcohol.
EDITOR: But people don’t chain smoke marijuana. Most use it recreationally, perhaps a couple of times a week; perhaps some once a day instead of a bottle of beer. Do you know anyone who only smokes a couple of cigarettes a week?