posted on Apr, 12 2011 @ 05:23 AM
How Does Marijuana Affect the Brain?
Scientists have learned a great deal about how THC acts in the brain to produce its many effects. When someone smokes marijuana, THC rapidly passes
from the lungs into the bloodstream, which carries the chemical to the brain and other organs throughout the body.
THC acts upon specific sites in the brain, called cannabinoid receptors, kicking off a series of cellular reactions that ultimately lead to the
"high" that users experience when they smoke marijuana. Some brain areas have many cannabinoid receptors; others have few or none. The highest
density of cannabinoid receptors are found in parts of the brain that influence pleasure, memory, thinking, concentrating, sensory and time
perception, and coordinated movement.1
Not surprisingly, marijuana intoxication can cause distorted perceptions, impaired coordination, difficulty with thinking and problemsolving, and
problems with learning and memory. Research has shown that, in chronic users, marijuana's adverse impact on learning and memory can last for days or
weeks after the acute effects of the drug wear off.2 As a result, someone who smokes marijuana every day may be functioning at a suboptimal
intellectual level all of the time.
Research into the effects of long-term cannabis use on the structure of the brain has yielded inconsistent results. It may be that the effects are too
subtle for reliable detection by current techniques. A similar challenge arises in studies of the effects of chronic marijuana use on brain function.
Brain imaging studies in chronic users tend to show some consistent alterations, but their connection to impaired cognitive functioning is far from
clear. This uncertainty may stem from confounding factors such as other drug use, residual drug effects, or withdrawal symptoms in long-term chronic
users.