Effects of Emerging Alcohol and Marijuana Use Behaviors on Adolescents’ Neuropsychological Functioning Over Four Years

Abstract

ABSTRACT. Objective:Adolescence is a period of neuromaturation concomitant with increased substance involvement. Most substance use studies of adolescents have focused on categorical classifications (e.g., dependent vs. nondependent), but little is known about the influence of specific substance use behaviors on cognitive functioning in youth. Method: This study prospectively evaluated the quantitative effects of different substance use behaviors on neuropsychological functioning. A cognitive test battery was administered at baseline (ages 12-14 years), before substance use initiation, and at follow-up (M = 4.0 years, SD = 2.0) to evaluate changes in verbal memory, visuospatial ability, psychomotor speed, processing speed, and working memory. Robust regressions examined substance use behaviors as predictors of neuropsychological functioning (N = 234). Results: Several substance use behaviors predicted follow-up neuropsychological functioning above and beyond effects of baseline performance on the same measure (ps < .05). Specifically, more alcohol use days predicted worse verbal memory ( { = -.15) and visuospatial ability ( { = -.19). More postdrinking effects ( { = -.15) and greater drug use ( { = -.11) predicted worse psychomotor speed. Processing speed was not predicted by substance involvement (ps > .05). Unexpectedly, more alcohol use predicted better working memory performance ( { = .12). Conclusions: The frequency and intensity of adolescent alcohol use may be more intricately linked to neuropsychological outcomes than previously considered. The low prevalence of substance use disorder in the sample suggests that subdiagnostic users may still experience adverse effects to verbal memory, visuospatial functioning, and psychomotor speed after initiating intense or frequent alcohol use. (J. Stud. Alcohol Drugs, 76, 738-748, 2015)

Cognitive, emotion control, and motor performance of adolescents in the NCANDA study: Contributions from alcohol consumption, age, sex, ethnicity, and family history of addiction.

“…Longitudinal studies have extended these findings, suggesting that verbal memory (Hanson, Cummins, Tapert, & Brown, 2011; Nguyen-Louie et al, 2015), psychomotor speed (Nguyen-Louie et al, 2015), visuospatial abilities (Hanson et al, 2011; Nguyen-Louie et al, 2015; Squeglia, Spadoni, Infante, Myers, & Tapert, 2009; Tapert & Brown, 1999; Tapert, Granholm, Leedy, & Brown, 2002), and attentional functioning (Squeglia et al, 2009; Tapert et al, 2002) appear to worsen following the initiation (Squeglia et al, 2009) or continuation (Hanson et al, 2011; Tapert et al, 2002) of heavy drinking during adolescence and early adulthood. Untoward effects were also detected in youth who drank alcohol but did not meet diagnostic criteria for alcohol use disorder (Nguyen-Louie et al, 2015; Squeglia et al, 2009). Because many functions continue to mature during adolescence and with pubertal development (e.g., Blakemore, Burnett, & Dahl, 2010; Hedman, van Haren, Schnack, Kahn, & Hulshoff Pol, 2012; Shaw et al, 2008; Sowell, Thompson, & Toga, 2004; Sullivan et al, 2011) (for review, Stiles & Jernigan, 2010), initiation of hazardous drinking in these years of change may have a detrimental effect on the maturing brain.…”

Alcohol and Drug Use and the Developing Brain

“…Alcohol use and drug withdrawal symptoms were related to worse verbal learning and memory, and stimulant use over the follow-up was related to worse visual learning and memory [50]. Heavier use patterns and greater hangover and withdrawal symptoms over time were related to worse cognitive functioning, suggesting a dose-dependent relationship between substance use and cognitive functioning [49] that has been replicated in other studies [48, 51]. Interestingly, youth who had met criteria for a substance use disorder at some point during the 10-year follow-up but remitted performed similarly to youth who had a persistent substance use disorder, suggesting heavy substance use during adolescence could have lasting effects into adulthood [50].…”

“…This is a particularly important area, as educational attainment is among the most critical developmental tasks of adolescence, and alcohol use and smoking behaviors at ages 12 to 14 predict lower educational achievement at later time points even after some confounding variables are taken into account [47]. In a sample of 234 healthy adolescents followed over 4 years, subdiagnostic alcohol and marijuana users showed worsening verbal memory, visuospatial functioning, and psychomotor speed after initiating intense or frequent alcohol and other substance use when compared to controls [48]. In a 10-year longitudinal study, heavy substance-using youth in treatment were assessed at age 16 and followed until early adulthood (~age 25).…”

Prospective changes in neural alcohol cue reactivity in at-risk adolescents

“…In the parent study, potential participants were excluded for psychiatric diagnoses, neurodevelopmental disorders, and use that exceeded minimal exposure to alcohol and other substances (Nguyen-Louie et al 2015). Participants were followed-up each year by phone to obtain data about alcohol consumption and other drug use habits and psychosocial changes (e.g., grade in school).…”