Official websites use. Share sensitive information only on official, secure websites. In light of the rapidly shifting landscape regarding the legalization of marijuana for medical and recreational purposes, patients may be more likely to ask physicians about its potential adverse and beneficial effects on health. The popular notion seems to be that marijuana is a harmless pleasure, access to which should not be regulated or considered illegal. Hashish is a related product created from the resin of marijuana flowers and is usually smoked by itself or in a mixture with tobacco but can be ingested orally.
Marijuana can also be used to brew tea, and its oil-based extract can be mixed into food products. The regular use of marijuana during adolescence is of particular concern, since use by this age group is associated with an increased likelihood of deleterious consequences 2 Table 1.
Although multiple studies have reported detrimental effects, others have not, and the question of whether marijuana is harmful remains the subject of heated debate. Here we review the current state of the science related to the adverse health effects of the recreational use of marijuana, focusing on those areas for which the evidence is strongest. The effect is strongly associated with initial marijuana use early in adolescence. Despite some contentious discussions regarding the addictiveness of marijuana, the evidence clearly indicates that long-term marijuana use can lead to addiction.
There is also recognition of a bona fide cannabis withdrawal syndrome 5 with symptoms that include irritability, sleeping difficulties, dysphoria, craving, and anxiety , which makes cessation difficult and contributes to relapse. Marijuana use by adolescents is particularly troublesome. The brain remains in a state of active, experience-guided development from the prenatal period through childhood and adolescence until the age of approximately 21 years.
This view has received considerable support from studies in animals, which have shown, for example, that prenatal or adolescent exposure to THC can recalibrate the sensitivity of the reward system to other drugs 10 and that prenatal exposure interferes with cytoskeletal dynamics, which are critical for the establishment of axonal connections between neurons. As compared with unexposed controls, adults who smoked marijuana regularly during adolescence have impaired neural connectivity fewer fibers in specific brain regions.
