Prior research has documented that White and Black adolescents use marijuana at similar rates, but Black young adults have significantly higher rates of use and Cannabis Use Disorder than their White counterparts. One potential contributor to this disparity may be neighborhood setting. A new study identified trajectories of marijuana use in young adulthood among a sample of primarily low-income Blacks in one U.S. city and investigated the relationship between neighborhood characteristics and marijuana use trajectory. Data were obtained from a larger community-based longitudinal study in which participants were recruited from students entering first grade in 1993 (N = 799). Data on the frequency of past-year marijuana use were collected annually via audio-computer assisted interviews. Roughly 88% of the sample (n = 700) completed at least one interview between 12th grade and age 21 and provided data on their marijuana use. The sample for the current study was restricted to individuals who completed at least one interview and remained living within the city at 12th grade (the point at which neighborhood environmental assessments were conducted; n = 378). Assessments of neighborhood factors at age 18 were obtained using the Neighborhood Inventory for Environmental Typology (NIfETy). NIfETy measures included physical disorder, alcohol and other drug activity (i.e., presence of drug paraphernalia, signs of drug selling), and positive social activity (i.e., youth playing outside). The authors also calculated the distance from participants’ homes to the nearest off-premise alcohol outlet using geographic information systems (GIS) software. Other variables included emergency and non-emergency narcotic calls for service reported to the local police department, violent crime locations and rates, percentages of families living in poverty, and percentages of female-headed households, as well as data on social transition factors (high school graduation, post-secondary education, employment, pregnancy/getting someone pregnant, and being a primary caregiver for a child). The authors used group-based trajectory modeling to identify patterns of past-year marijuana use from age 18 to 21. Three marijuana use groups were identified: No Use (68.8%), Declining Use (19.6%; those who reported, on average, using marijuana three to four times during the past year at age 18 and no use at age 21), and Chronic Use (11.7%; those who reported, on average, using marijuana five to nine times in the past year at age 18, 10-19 times at ages 19 and 20, and five to nine times at age 21). After participants were assigned to trajectory groups, multinomial regression models were used to explore associations among neighborhood and social transition factors for each group, adjusting for individual-level factors. Results of the multinomial regression analysis indicated living in neighborhoods with more positive social activity increased the odds of membership in the Declining Use group (adjusted odds ratio [AOR] = 1.21; 95% confidence interval [CI] = 1.02, 1.43; p = 0.03) compared to the No Use group. Relative to the No Use group, living further from an alcohol outlet decreased the odds of belonging to the Chronic Use group (AOR = 0.13; 95% CI = 0.02, 0.78; p = 0.03), while living in neighborhoods with higher proportions of female-headed households (AOR = 1.06; 95% CI = 1.00, 1.12; p = 0.04) and higher rates of violent crime (AOR = 1.97; 95% CI = 0.99, 3.91; p = 0.05) increased the odds of membership in this group. Additionally, graduating from high school was associated with a decreased risk of belonging to the Declining Use group, relative to the No Use group. There were no significant relationships observed between obtaining post-secondary education and group membership.

Take away: Participants were sorted into three groups based on their marijuana use trajectories: No use, declining use, and chronic use. Results indicated neighborhood factors (i.e., poverty, social activity) and social transitions (i.e., high school graduation,  parenthood) can affect the odds of membership in these groups.

Reboussin, B.A., Ialongo, N.S., Green, K.M., Furr-Holden, D.M., Johnson, R.M. & Milam, A.J. (2018). The impact of the urban neighborhood environment on marijuana trajectories during emerging adulthood. Prevention Science [published online ahead of print May 29, 2018] doi: 0.1007/s11121-018-0915-4