What effects does marijuana have on the brain/body?

Many complex effects: Marijuana has a wide range of effects & this varies from person to person. There are also many strains, some more stimulating & some more sedating. It can be calming, ease muscle tension, stimulate appetite, relieve nausea & aid sleep but may impair memory & concentration. Marijuana contains over 100 different medically active compounds & we are still learning what they do.See my comments for links.

Marijuana effects: Marijuana distorts perceptions, impairs coordination, thinking, problem solving, learning, and memory. Can trigger acute psychotic reaction along with onset or relapse of schizophrenia in vulnerable individuals. Increases heart rate a lot; one source showed smokers almost 5 times as likely to have heart attack in 1st hour. Mj irritates lungs & has more carcinogens than regular cigarettes.