Is Marijuana Use Safe? NIDA’s Director Addresses Questions of Adverse Health Effects

In the US, marijuana is the most common “illicit” substance (its legal status varies by state) with roughly 12% of individuals over the age of 12 reporting current use. Changes in state laws have created a complicated landscape whereby some have decriminalized possession, some have passed medical marijuana laws, and others (Colorado and Washington) have legalized marijuana for recreational purposes. One of the consequences of these changes is that, more than ever, Americans are questioning whether any risk is involved with marijuana use. In this important review, Dr. Nora Volkow (director of the National Institute on Drug Abuse) and colleagues outline the adverse health effects of marijuana use and the strength of the evidence supporting its health impact.

• The effects of short-term use include: impaired short-term memory and motor coordination, altered judgment, and, in high doses, paranoia and psychosis.†
• Long-term marijuana use is associated with the development of addiction in 9% of people with marijuana use overall, 17% of those who begin use in adolescence, and 25–50% of those who report daily use.*† Whether it leads to use of other drugs remains controversial.†
• Other long-term effects include: altered brain development,*† poor educational outcomes,* cognitive impairment,* diminished life satisfaction and achievement,*† impaired driving ability,† symptoms of chronic bronchitis,† and increased risk of psychotic disorders in people who are predisposed.†

Comments:

The availability and social acceptability of marijuana, as well as its pharmacologic properties, have resulted in an increasing prevalence of use. This exposure is not without risk to an individual’s health, especially with long term use and use beginning in adolescence.

Jeanette M. Tetrault, MD

Reference:

Volkow ND, Baler RD, Compton WM, Weiss SR. Adverse health effects of marijuana use. N Engl J Med. 2014;370(23):2219–2227.