Four percent of the world’s population has used marijuana in a given year, according to the World Health Organization.
In the United States, the lifetime prevalence of marijuana use is 42 to 46 percent. Meanwhile, use appears to be increasing, aided in part by laws in several states, including Colorado, making marijuana use legal for either medical indications or recreational use.
Marijuana, also referred to as cannabis, contains more than 400 compounds, but its primary psychoactive component is delta-9-tetrahydrocannabinol, commonly abbreviated THC. After absorption, THC readily crosses into brain tissue and binds receptors that stimulate the release of brain chemicals in the brain’s reward center. The result is symptoms of intoxication.
Cannabis ingestion usually leads to a “high,” with enhanced mood and a pleasurable feeling. This is often accompanied by a decrease in anxiety and alertness as well as a reduction in inhibitions. Cannabis intoxication may result in imbalance when walking, slurred speech and increases in heart rate, blood pressure and breathing rate. Rarely, chest pain or heart attack may occur in susceptible individuals.
Use is associated with impaired attention, concentration, short-term memory and ability to assess risk, leading to impaired judgment. These latter effects often persist well beyond the “high feeling” and can last up to 24 hours because of accumulation of the drug in fatty tissues.
Large overdoses, sometimes associated with inadvertent consumption of cannabis containing foods by children, may produce coma, decreased breathing, seizures and even death.
Cannabis is an addictive drug. Cannabis dependence is marked by a repeated pattern of use and intoxication over a long period of time leading to social, occupational and legal problems. Repeated, long-term and heavy use can lead to tolerance, with loss of the pleasurable effects of the substance. Sudden discontinuation of cannabis use in dependent persons may produce withdrawal symptoms ranging from tiredness and depression to anxiety and irritability.
The use of marijuana for medical purposes, while legal in several states including Colorado, remains very controversial. Among registered patients receiving medical marijuana in states where it is legal, more than 90 percent of use is related to pain management. Unfortunately, there are no good clinical studies that have shown marijuana use to be more effective than traditional pain-management strategies, either alone or in combination with other treatments.
There are a number of potential medical effects from long-term cannabis use. It is believed that smoking cannabis likely increases the risk of certain cancers, including lung cancer. Long-term use of cannabis may be linked to problems with memory, attention and higher-level brain function. Studies have shown a link between cannabis use and the risk of psychotic disorders including schizophrenia.
Dr. Matthew A. Clark is a board-certified physician practicing at the Ute Mountain Ute Health Center in Towaoc.