Marijuana affects both the cardiovascular and central nervous systems. The major psychoactive component in marijuana is delta-9-tetrahydrocannabinol, or THC. After entering the bloodstream through blood-gas exchanges associated with smoking, THC combines with receptor sites in the human brain to cause drowsiness, increased appetite, giddiness, hallucinations, and other psychoactive effects. Although the causative mechanisms are not fully known, current research indicates that THC ingestion results in THC binding to receptor sites associated with measurable memory loss. Other studies correlate THC binding to receptors in the cerebellum and correlated decreases in motor coordination and/or the ability to maintain balance. At low doses there tends to be a sense of well-being, drowsiness, and relaxation. As the dose increases, other effects take place such as an altered sense of time and sensory awareness, difficulty in balancing and remembering from one moment to another (short-term memory). Conversation and thoughts become incomplete, and exaggerated laughter may take place with increased doses. At higher doses, severe psychological disturbances can take place such as paranoia, hallucinations, panic attacks, and the acting out of delusions.
The cardiovascular system is affected by an increased heart rate and dilation of eye blood vessels. The American Heart Association maintains that marijuana smoking may induce heart attacks. Difficulty in coordinating body movements and pains in the chest may be other effects of the drug. Heavy users may experience a decrease in immune function. Males who smoke marijuana could also experience a decreased sperm count. Less is known about marijuana's effects on the lungs than cigarette smoking, but the evidence points to long-term damage similar to the effects of tobacco smoking. Chronic users suffer from throat irritation, persistent cough, chronic bronchitis, and emphysema.
The FDA, in 1985, gave approval for the use of two psychoactive chemicals from marijuana to prevent nausea and vomiting after chemotherapy in cancer treatment. THC can be prescribed in capsule form for these patients. Research suggests that compounds, other than THC, inhaled when smoking marijuana can also be used for medicinal purposes. Marijuana may help stop the weight loss in AIDS patients, it might lower eye pressure in people with glaucoma, it may control spasms in multiple sclerosis patients, and it could be used to relieve chronic pain.
See also Addiction.
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Jordan P. Richman