Public Perception of Cannabis Potency and Public Health Risks Associated with Cannabis Use

Background/Purpose: Although cannabis is the one of the most commonly used substances, its use has been connected to adverse outcomes including motor-vehicle crashes (Asbridge, Hayden and Cartwright, 2012) and accidental injuries (Hall & Degenhart, 2009). Understanding public perceptions of risks associated with cannabis is important as cannabis policy is rapidly evolving and support for marijuana legalization is increasing. This study examines public perceptions of public health risks associated with cannabis use among a state-wide sample of adults in Michigan.

Methods:  Data were collected using web-based surveys administered during a three week period (August-September 2016). Participants (N=2191) were recruited through online and email advertisements from community based agencies and a statewide advocacy coalition. Measures were adapted from previous public opinion research with input from advocacy coalition members. Logistic regression models were used to assess public perceptions of cannabis potency and perceived impact of marijuana legalization on road safety, employee safety, and emergency department (ED) visits. Independent variables included demographics, political orientation, and marijuana-related variables (past marijuana use, attitude toward marijuana legalization).

Results: Respondents ranged in age from 18 to 88 years (Mean=45.5 years) and were 72% female. Most adults (79.5%) were aware that marijuana is more potent today compared to the past. Adults who reported recent (OR=1.77) or past marijuana use (OR=1.31), supported marijuana legalization (OR=1.39), or had graduate degrees (OR=1.40) had greater odds of recognizing marijuana is more potent. About half (55.2%) of the sample felt marijuana legalization would negatively affect road safety. Older age (OR=1.01), a graduate degree (OR=2.23) or bachelor’s (OR=1.67) degree were associated with greater odds of expecting roads to be less safe with legalization. Recent marijuana use (OR=0.17), supporting legalization (OR=0.02), and being unsure (OR=0.12) about marijuana legalization were associated with lower odds of expecting roads to be less safe. Sixty-three percent of adults felt marijuana legalization will negatively affect employee safety. Older age (OR=1.01) and African-American race (OR=2.17) were associated with greater odds of expecting employee safety to decrease with legalization. Recent marijuana use (OR=0.41), supporting marijuana legalization (OR=0.02), and being unsure about marijuana legalization (OR=.14) were associated with lower odds of expecting employee safety to decrease. About 58.9% of respondents thought marijuana legalization would lead to an increase in ED visits. A graduate degree (OR=1.88) was associated with greater odds of expecting ED visits to increase with marijuana legalization. Recent marijuana use (OR=0.43), female gender (OR=0.67), supporting marijuana legalization (OR=0.03), and being unsure about marijuana legalization (OR=0.11) were associated with lower odds of expecting ED visits to increase with marijuana legalization. 

Conclusions & Implications: Although most adults recognize potential public health risks associated with cannabis legalization, a sizable minority of adults do not feel marijuana legalization will have negative public health consequences. These adults may not recognize that cannabis can impair driving and increase employee accidents and ED visits. Prevention and education may be needed to reduce negative public health consequences associated with cannabis use.