Following the legalization of recreational marijuana use in Colorado and Washington, the most popular illicit drug in the United States has garnered the national spotlight. Critics and advocates for pot have presented their own reasoning behind why cannabis should either be made legal or illegal. All of these differing opinions have only helped to misconstrue the actual facts and fiction regarding marijuana use.

World Health Organization Expert Advisor on Addiction Professor Wayne Hall reviewed existing cannabis research dating back to 1993 to help shed light on the effect marijuana has on mental and physical health. The Centers for Disease Control and Prevention reported that the amount of high school students who admitted to using marijuana one or more times during their life has risen from 31.3 percent in 1991 to 40.7 percent in 2013.

According to Hall’s findings, acute cannabis use cannot result in a fatal overdose, but people who use cannabis regularly can develop a dependence syndrome. The risk of a dependence syndrome is an estimated one in 10 for all cannabis users and one in six among those who start is adolescence. Adolescent cannabis users are also more likely to use other illicit drugs and have lower educational attainment compared to their non-using peers. “But, we don’t whether the link is casual,” Hall said.

Hall found that regular cannabis use can have a significant impact on mental health. For example, chronic marijuana use can double a person’s risk of experiencing psychotic symptoms or disorders, especially if they have a personal or family history of such behavior. Adolescents who use marijuana regularly also double their risk of reporting psychotic symptoms or being diagnosed with schizophrenia by the time they reach adulthood.

Smoking marijuana regularly can also increase a person’s risk for chronic bronchitis and the possibility of a heart attack. Babies born to mothers who use cannabis during pregnancy often suffer from low birth weight. The WHO reported that using cannabis during pregnancy can lead to postnatal risk of certain types of cancer and impairment in fetal development.

Source: Hall W. What has research over the past two decades revealed about the adverse health effects of recreational cannabis use? Addiction. 2014.