Examining the influence of adolescent marijuana use on adult intelligence: Further evidence in the causation versus spuriousness debate

Commentary on Meier et al. (2018): Smoke and mirrors—are adolescent cannabis users vulnerable to cognitive impairment?

“…As Meier et al . discuss, these findings are in line with a number of recent prospective cohort studies on cannabis use and neurocognitive performance, in which outcomes were assessed during adolescence or early adulthood . Of interest, Meier et al .…”

Associations between adolescent cannabis use and neuropsychological decline: a longitudinal co‐twin control study

“…To address these questions, prospective longitudinal studies are needed. There are only nine cohort studies of the association between cannabis use and neuropsychological impairment that could inform these questions . These studies included adolescents or young adults in the sample and administered neuropsychological tests at two or more time‐points (Supporting information, Table S1 ).…”

“…There are only nine cohort studies of the association between cannabis use and neuropsychological impairment that could inform these questions . These studies included adolescents or young adults in the sample and administered neuropsychological tests at two or more time‐points (Supporting information, Table S1 ). Six of these studies assessed neuropsychological functions in childhood, prior to cannabis use initiation, and therefore had ‘before and after’ assessments of neuropsychological functions .…”

“…These studies included adolescents or young adults in the sample and administered neuropsychological tests at two or more time‐points (Supporting information, Table S1 ). Six of these studies assessed neuropsychological functions in childhood, prior to cannabis use initiation, and therefore had ‘before and after’ assessments of neuropsychological functions . These six studies found inconsistent evidence for the hypothesis that neuropsychological impairment predates cannabis initiation .…”

“…Six of these studies assessed neuropsychological functions in childhood, prior to cannabis use initiation, and therefore had ‘before and after’ assessments of neuropsychological functions . These six studies found inconsistent evidence for the hypothesis that neuropsychological impairment predates cannabis initiation .…”