Marijuana: Mental effects
Last modified: Sunday, 31. May 2009 - 5:03 pm
Users often experience a mellow sense of well-being and relaxation that makes them feel expansive, creative, and more sensitive to all types of stimuli. Perception of time slows, and ability to gauge distance, depth, and speed accurately is distorted. Users can also spiral downward into anxiety, paranoia, panic attacks, and hallucinations. This effect is more pronounced when larger doses of THC are ingested, such as when hashish or other more concentrated forms of marijuana are used. Higher doses are also possible when marijuana is eaten rather than smoked; this occurs when more of the drug is ingested before it can be metabolized.
Within seconds of entering the bloodstream, the cannabinoids in marijuana bind to special areas in the brain called THC receptors. These regions, located throughout the brain, are heavily concentrated in the hippocampus, which controls learning and memory. This means that one of marijuana’s most pronounced effects is its interference with the ability to form short-term memories. A 1996 study published in the Journal of the American Medical Association showed that heavy marijuana users, defined as those who ingest the drug on a daily or nearly daily basis, scored significantly lower on learning and other tests.
Other studies of heavy marijuana users show that the drug inhibits the ability to focus attention, learn new information, and solve problems as long as two days after taking it. This most likely occurs because THC changes the way the brain processes new information; THC stifles neural activity in the hippocampus by suppressing acetylcholine release. Long-term use can cause changes in users’ brains that are similar to those caused by other controlled substances.