Marijuana Use among Juvenile Arrestees: A Two-Part Growth Model Analysis

Abstract

This article examines the impact of sociodemographic characteristics and psychosocial factors on the probability and frequency of marijuana use and, for youths initiating use, on their frequency of use over four time points. The sample consists of 278 justice-involved youths completing at least one of three follow-up interviews as part of a National Institute on Drug Abuse (NIDA)–funded study. A two-part growth model was estimated to examine the probability of engaging in marijuana use and change in marijuana frequency of use over time. In addition, covariates for intervention status, gender, age, race, ethnicity, psychological functioning, alcohol use, and self-reported delinquency were included as baseline predictors in the model. The results of our two-part latent growth model reveal (1) a latent tendency to engage in marijuana use and a conditional, continuing decision on frequency of marijuana use, and (2) different patterns of relationships among age, psychosocial variables, and the probability and frequency of marijuana use. Implications for analytical, policy, and intervention service needs are discussed.

KEYWORDS:

• juvenile delinquents
• marijuana use
• two-part growth model

This article was prepared from data collected as part of Grant #1-RO1-DA08707, funded by the National Institute on Drug Abuse. The authors are grateful for their support. However, the research results reported and the views expressed in the article do not necessarily imply any policy or research endorsement by the funding agency.

Notes

¹In order to evaluate the validity of the youths' self-reported delinquency, self-reported delinquency was compared to official records of arrests or charges. A low rate of denial of official delinquency compared to the rate of admission for delinquency among youths without an official record suggested most youths reported their delinquency accurately.

²Arguably, youths who were not able to access substances for use due to time spent in secure facilities (e.g., detention, residential treatment) would not have equivalent time at risk for such behavior. Examination of the distribution of time spent in a secure facility indicated relatively few youths had time at risk small enough to influence their drug use scores. Therefore, self-reported use of marijuana was not corrected for time at risk since such a refinement in scoring would not have had an appreciable effect on the analyses.

³It is important to note that time of entry into the study determined the number of follow-up interviews each youth received. Hence, the data that are missing are a consequence of the design of the study.

∗p < .05.

∗p < .05.

χ² (10, N = 278) = 16.828, p = .08.

∗p < .05.