Unfazed or Dazed and Confused: Does Early Adolescent Marijuana Use Cause Sustained Impairments in Attention and Academic Functioning?

Abstract

There is some suggestion that heavy marijuana use during early adolescence (prior to age 17) may cause significant impairments in attention and academic functioning that remain following sustained periods of abstinence. However, no longitudinal studies have examined whether both male and female adolescents who engage in low (less than once a month) to moderate (at least once a monthly) marijuana use experience increased problems with attention and academic performance, and whether these problems remain following sustained abstinence. The current study used within-individual change models to control for all potential pre-existing and time-stable confounds when examining this potential causal association in two gender-specific longitudinal samples assessed annually from ages 11 to 16 (Pittsburgh Youth Study N=479; Pittsburgh Girls Study N=2296). Analyses also controlled for the potential influence of several pertinent time-varying factors (e.g., other substance use, peer delinquency). Prior to controlling for time-varying confounds, analyses indicated that adolescents tended to experience an increase in parent-reported attention and academic problems, relative to their pre-onset levels, during years when they used marijuana. After controlling for several time-varying confounds, only the association between marijuana use and attention problems in the sample of girls remained statistically significant. There was no evidence indicating that adolescents who used marijuana experienced lingering attention and academic problems, relative to their pre-onset levels, after abstaining from use for at least a year. These results suggest that adolescents who engage in low to moderate marijuana use experience an increase in observable attention and academic problems, but these problems appear to be minimal and are eliminated following sustained abstinence.

Early predictors of maturing out of marijuana use among young men

“…Boys who scored in the top 30% and an approximately equal number randomly selected from the remainder were selected for follow-up ( N = 503). The follow-up sample did not differ significantly from the screening sample on race, family composition, and California Achievement Test reading scores (Pardini et al, 2015). The boys’ mean age at screening was 6.9 ( SD = 0.5).…”

“…It is critical to differentiate adolescence-limited from continuing users because some negative effects of regular marijuana use (e.g., cognitive impairment) can rebound following periods of sustained abstinence (see Pardini et al, 2015), and cumulative exposure may be more critical to the development of long-term problems than age of onset (Labouvie & White, 2002; Meier et al, 2012). Thus, if we can identify early risk factors that increase the probability of continued use, we may be in a better position to intervene before problems develop.…”

Investigating causal pathways between liability to ADHD and substance use, and liability to substance use and ADHD risk, using Mendelian randomization

“…There is tentative evidence that there may be causal effects in the other direction (i.e., substance use leading to an increase in ADHD symptoms) 24,25 . In monozygotic twin pairs discordant for smoking, the smoking twin scored higher on attention problems -a difference which only appeared after smoking was initiated 24 .…”

Early marijuana initiation: The link between prenatal marijuana exposure, early childhood behavior, and negative adult roles

“…Frequent cannabis use before the age of 16 predicted significantly higher rates of substance use, delinquency, unemployment, and educational difficulties among teens (Fergusson & Horwood, 1997). By contrast, Pardini et al (2015) found no association between EAOM (defined as <17 years) and adolescent attention problems or academic performance, although this might reflect the fact that their subjects had low to moderate levels of use and were past the age when marijuana use becomes normative.…”