Over at Seattle Children's Teenology 101, an adolescent medicine physician posted information about teen marijuana use. Here is an excerpt:
Popular movies and TV shows frequently refer to marijuana use as if it’s normal
and perfectly acceptable (have you seen the movie Friday or watched That 70′s
Show?), yet rarely portray any of the dangers. The harmful health effects of
marijuana include worsening of lung function, lack of motivation, increased
appetite, poor concentration, poor sleep, and even gynecomastia (or breast
tissue development) in males.
More information about adolescent marijuana use may be found at:
-- the Alcohol & Drug Abuse Institute at the University of Washington;
-- the Journal of the American Medical Association reporting on a study that found that "persistent marijuana use beginning in adolescence is associated with a decline
in cognitive function by midlife . . ."
-- the American Academy of Pediatrics statement about marijuana policy.