Smoking cannabis for recreational purposes has deep historical roots. Also known as marijuana or reefer, cannabis is a controlled substance in many countries, including the U.S. and Britain. In general, the effects of smoking cannabis include changes in mental functioning and impaired motor functions. Long-term effects may be harmful, particularly for the lungs and pulmonary system.
Short-Term Effects
Changes in perception and mood occur within 10 minutes of smoking the leaves and buds of cannabis plants. Typically, effects include euphoria, relaxation and feelings of detachment, according to a 2001 study titled "Psychiatric Effects of Cannabis" in the "British Journal of Psychiatry." Other short-term effects include reduced short-term memory, enhanced visual perception, changes in the perception of time and reduced coordination and balance. A minority of users also experience anxiety, panic or depression. Further, cannabis may instigate psychosis to those with preexisting psychiatric disorders.
Cannabis also has a reputation for its ability to block pain in the short term, spurring medical marijuana initiatives in 14 U.S. states for reducing the chronic pain of cancer and other end-of-life conditions. Yet, the evidence for the effectiveness of cannabis over other medications is unconvincing for many in the medical community, according to the U.S. Drug Enforcement Administration.
Lingering Effects
Cannabis, unlike many recreational drugs such as alcohol, has a relatively long half-life in the body, because cannabinoids are fat soluble and store in the body's fat cells. Delta9-tetrahydrocannabinol (THC), the most active cannabinoid in marijuana, can be detected for 3 to 10 days in the blood stream after ingestion, according to the The National Institute of Drug Abuse. Mental performance, especially with complex tasks, has been shown to be reduced for up to 24 hours after ingestion.
However, most studies of lingering effects have used long-term cannabis users for subjects. An exception to this trend was a 1998 study published in "Pharmacology, Biochemistry and Behavior," which tested physical and mental performance in non-long-term users the day after smoking one marijuana cigarette. Researchers found no measurable residual effects.
Long-Term Effects
Long-term mental effects of cannabis are largely unknown, and unfortunately many studies have not controlled for recent use of cannabis in subjects, therefore creating confusion between long-term and lingering effects. A 2001 study published in the "Archives of General Psychiatry" found no significant neuropsychological differences between long-term users and short-term cannabis users, based on a battery of word and memory tests. The researchers concluded there remains no evidence of a cumulative effect on the brain for smoking cannabis.
Long-term physical effects, on the other hand, are more visible. As in tobacco use, when cannabis is burned many harmful chemicals and carcinogens are inhaled. Regular smoking of marijuana has serious long-term effects on the lungs and the pulmonary system. A 2005 study published in the "Mondalvi Archives for Chest Disorders" found good evidence for chronic coughing, chronic inflammation of the airways and the disruption of healthy epithelial cells, all of which may be precursors to lung cancer.
References
- "British Journal of Psychiatry": Psychiatric Effects of Cannabis
- "U.S. Drug Enforcement Administration": Exposing the Myth of Smoked Medical Marijuana
- "Pharmacology Biochemistry and Behavior": Acute and Residual Effects of Marijuana in Humans
- "Archives of General Psychiatry": Neuropsychological Performance in Long-term Cannabis Users
- "Mondalvi Archives for Chest Disorders": Smoked Marijuana as a Cause of Lung Injury
