President Barack Obama publically conveyed his doubts regarding the assumption that marijuana is a more dangerous substance compared to alcohol this past January. As the debate over marijuana legalization grows, especially with a looming presidential election, pot advocates regularly argue that cannabis is a safer alternative compared to alcohol, but minimal evidence exists to back up either claim. A recent study conducted at New York University’s Center for Drug Use and HIV Research (CDUHR) set out to determine how the adverse effects of smoking marijuana compare to alcohol use.

“The paucity of research is of particular public health concern as alcohol and marijuana are the two most commonly used psychoactive substances among adolescents,” Dr. Joseph J. Palamar, assistant professor of Population Health at NYU Langone Medical Center (NYULMC), said in a statement. “Nearly half of high school seniors have used marijuana in their lifetime and over two-thirds have used alcohol, but few studies have compared adverse psychosocial outcomes of alcohol and marijuana directly resulting from use.”

Palamer and his colleagues gathered data from 7,437 high school students (average age of 18), who reported using alcohol or marijuana at least once in their lifetime. High school seniors who were enrolled in the Monitoring the Future study were asked if they had ever experienced any adverse psychosocial outcomes due to alcohol or marijuana use. Researchers found that the adverse effects of marijuana and alcohol are rarely mutually exclusive among teens. These outcomes tend to vary across gender and racial/ethnic backgrounds and are often due to marijuana’s legal status or societal stigma.

“Not unexpectedly, we found that the higher the frequency of use, the higher the risk of reporting an adverse outcome,” Palamar said. “In particular, the relationship between frequent alcohol use and regret was much stronger than the relationship between frequent marijuana use and regret. The most alarming finding was that alcohol use was highly associated with unsafe driving, especially among frequent drinkers. Compared to non-drinkers, frequent drinkers were over 13 times more likely to report that their alcohol use has led to unsafe driving. Marijuana users, compared to non-users, were three times more likely to report unsafe driving as a direct result of use.”

Teenagers who use marijuana are more likely to be viewed in a negative light, most notably by authority figures, and also stand a higher risk of facing legal ramifications compared to those who drink alcohol. Marijuana use was also associated with being involved with people who were a so-called “bad influence,” possibly because marijuana is illegal and users are susceptible to a stigma or disapproval. On the other hand, high school seniors, females more often than not, were more likely to report feeling less emotionally stable and were not able to think as clearly due to their alcohol use.

Marijuana and alcohol also have differing adverse outcomes in terms of relationships with significant others, peers, and authority figures. While high school seniors were more likely to report problems within a relationship between their friend or boyfriend/girlfriend that were caused by alcohol use, those who used marijuana had a troubled relationship with their teachers or supervisors. Unfortunately, this poor relationship with authority figures usually led to a lack of interest and energy, which caused poor school and job performance among marijuana users.

“As a controled substance, mere possession of marijuana may increase the risk of significant legal consequences compared to an age-restricted legal substance such as alcohol, so this was not unexpected." Palamar added. “Smoking marijuana also tends to leave a strong odor, which can easily draw attention to authorities. However, we found no racial differences with regard to getting in trouble with police because of marijuana use. Results might have been different if we focused on older individuals or only those who reside in big cities.”

Source: Weitzman M, Cleland C, Ompad D, Kamboukos D, Fenstermaker M, Palamar J. Adverse psychosocial outcomes associated with drug use among US high school seniors: a comparison of alcohol and marijuana. American Journal of Drug and Alcohol Abuse. 2014.