Temporal Substance Use Problems Among Young Adults Who Use Legal Performance-Enhancing Substances

Background and Purpose: Legal performance-enhancing substances (i.e. creatine) are widely used among adolescent and young adult males; however, little is known about their temporal associations with substance use behaviors. Guided by the Gateway Hypothesis of substance use, this study had two specific aims. First, this study aimed to identify the prospective association between adolescent substance use (alcohol, cigarette, and marijuana) and use of legal performance-enhancing substances in young adulthood. Second, this study aimed to identify the prospective association between use of legal performance-enhancing substances in young adulthood and substance use-associated risk behaviors in adulthood.

Methods: We analyzed prospective cohort data from the National Longitudinal Study of Adolescent to Adult Health, Waves I-IV (1994-2008). Logistic regressions were used to first assess adolescent substance use (Wave I) and use of legal performance-enhancing substances (Wave III) and second to assess use of legal performance-enhancing substances (Wave III) and subsequent substance use-associated risk behaviors (Wave IV), adjusting for potential confounders including Wave I and III substance use.

Results: Among the sample of 12,133 young adults aged 18-26 years, 16.1% of males and 1.2% of females reported using legal performance-enhancing substances in the past year. Adolescent alcohol use was prospectively associated with higher odds of legal performance-enhancing substances use in young men (AOR 1.39, 95% CI 1.13-1.70). Among young men, legal performance-enhancing substances use was prospectively associated with higher odds of alcohol-related behaviors including binge drinking (AOR 1.35, 95% CI 1.07-1.71), injurious and risky behaviors (AOR 1.78, 95% CI 1.43-2.21), legal problems (AOR 1.52, 95% CI 1.08-2.13), reducing activities and socialization due to alcohol use (AOR 1.91, 95% CI 1.36-2.78), and emotional or physical health problems (AOR 1.44, 95% CI 1.04-1.99). Among young women, legal performance-enhancing substances use was prospectively associated with higher odds of alcohol-related behaviors including emotional or physical health problems (AOR 3.00, 95% CI 1.20-7.44).

Conclusions and Implications: Use of legal performance-enhancing substances should be considered a gateway to future alcohol-related risk behaviors, particularly among young men. Social work practitioners and clinicians should be assessing legal performance-enhancing substances use among boys and men in order to provide appropriate interventions. Lastly, these results provide further evidence for the need for federal and state legislation, oversight, and regulation of legal performance-enhancing substances.