Prospective, longitudinal study to isolate the impacts of marijuana use on neurocognitive functioning in adolescents

Abstract

IntroductionPolicies to legalize possession and use of marijuana have been increasingly supported across the United States. Although there are restrictions on use in minors, many substance abuse scientists anticipate that these policy changes may alter use patterns among adolescents due to its wider availability and a softening of beliefs about its potentially harmful consequences. Despite the possibility that these policies may increase the prevalence of use among adolescents, the effects of marijuana on neurodevelopment remain unclear, clouding arguments in favor of or opposition to these policies.MethodsThe present prospective, longitudinal study was designed to isolate the neurodevelopmental consequences of marijuana use from its precursors during adolescence—a period of heightened vulnerability for both substance use and disrupted development due to environmental insults. Early adolescents who were substance-naïve at baseline (N = 529, aged 10–12) were recruited and tracked into adolescence when a subgroup initiated marijuana use during one of three subsequent waves of data collection, approximately 18 months apart.ResultsResults suggest that marijuana use may be specifically related to a decline in verbal learning ability in the short term and in emotion recognition, attention, and inhibition in the longer-term.DiscussionThese preliminary findings suggest that marijuana use has potential to adversely impact vulnerable neurodevelopmental processes during adolescence. Intensive additional investigation is recommended given that state-level policies regulating marijuana use and possession are rapidly shifting in the absence of good scientific information.

Medical Marijuana Had No Impact on Amphetamine Prescribing in Medicaid

“…There were several limitations and caveats which should be considered. The potential neurocognitive effects with use of marijuana develop over a long period of time [5]. Studies have linked this long-term use to problems with controlling emotions, executive functioning, and even problem solving [4].…”

“…Studies have linked this long-term use to problems with controlling emotions, executive functioning, and even problem solving [4]. Other studies have linked long term use to problems with attention and short-term learning [5,6]. These potential symptoms mirror patients with ADHD as attentiveness, hyperactivity and problems with executive functioning are all linked to this disorder as well [6].…”

“…One study found that long-term cannabis use impaired cognitive function to varying degrees, which may include emotional control, problem-solving abilities, and executive functioning [4]. Another longitudinal investigation concluded that marijuana use over time impacts short term learning, attention, and inhibition [5].…”

“…One study found that long-term cannabis use impaired cognitive function to varying degrees, which may include emotional control, problem-solving abilities, and executive functioning [4]. Another longitudinal investigation concluded that marijuana use over time impacts short term learning, attention, and inhibition [5]. Many of the effects have similar characteristics to attention-deficit/hyperactivity disorder (ADHD), including inattention, forgetfulness, hyperactivity, and deficits in executive cognitive functioning [6, 7].…”

Emotion Recognition and Self-Reported Emotion Processing in Alcohol and Cannabis Co-Using Young Adults

“…In contrast, using a dynamic emotion recognition task in which facial expressions gradually changed in expression, frequent cannabis users had slower emotion recognition abilities relative to the controls but no differences in their overall recognition accuracy [21]. Finally, a recent longitudinal study examining the effect of cannabis use initiation during adolescence on emotion recognition abilities found decreases in emotion recognition accuracy with more frequent cannabis use by late adolescence [22]. These differences across studies could be related to variations in task design (static vs. dynamic facial expressions) and substance use characteristics (abstinent vs. current frequent cannabis users) of the participants included.…”