A Systematic Review of the Prevalence and Correlates of Adolescent Solitary Alcohol and Other Drug Use

Introduction: Use of alcohol and other drugs is common and tends to be a social phenomenon among adolescents. Some youth, however, engage in drug use when they are alone. Adolescent solitary relative to social-only drug use may have a unique etiology and, independent of the amount and frequency of use, distinct developmental consequences, such as progression to substance use disorder (SUD). This article provides the first systematic review of the (1) prevalence and (2) correlates, including possible predictors and consequences, of solitary drug use among middle school- and high school-age adolescents. Such knowledge is needed to guide the development of early screening and solitary drug use prevention efforts.

Methods: This review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) methodology. Electronic databases searched were PubMed, PsycINFO, and Web of Science. Articles were included if they mention solitary alcohol or other drug use among adolescents, ages 12-18 years. Exclusionary criteria included studies on non-human animals, college students only (a select population of young adults), non-English language publications, and articles that were exclusively about solitary tobacco use. Overall, 27 articles were selected for review.

Results: The prevalence of adolescent solitary drug use varies by the nature of the sample (community or clinical) and the type of drug (alcohol, marijuana, illicit drugs), and is elevated in current drug users and other subgroups (e.g., males; lesbian, gay, and bi-sexual youth). Predictors of solitary drug use include stress, coping, and negative emotions. Solitary drug use also is associated with early initiation of use and subsequent SUD symptoms, as well as diminished academic performance and health.

Conclusions: Solitary drug use is not uncommon among adolescents, particularly in vulnerable groups, and may have a unique etiology compared to social-only use reflecting attempts to self-medicate or cope with stress. Solitary drug use also appears to have distinct drug-related and psychosocial consequences. Although existing drug use prevention programs have been shown to have salubrious effects, they might need to be supplemented to have an enhanced impact on solitary drug involvement. Further research elucidating the epidemiology and etiology of solitary drug use can aid in efforts to identify, as early as possible, at-risk youth and direct them toward preventive interventions designed, for example, to teach prosocial coping skills as alternatives to drinking and using drugs alone.