Importance: Cannabis use during adolescence and young adulthood may affect academic achievement; however, the magnitude of association remains unclear.
Objective: To conduct a systematic review evaluating the association between cannabis use and academic performance.
Data sources: CINAHL, EMBASE, MEDLINE, PsycInfo, PubMed, Scopus, and Web of Science from inception to November 10, 2023.
Study selection: Observational studies examining the association of cannabis use with academic outcomes were selected. The literature search identified 17 622 unique citations.
Data extraction and synthesis: Pairs of reviewers independently assessed risk of bias and extracted data. Both random-effects models and fixed-effects models were used for meta-analyses, and the Grading of Recommendations Assessment, Development, and Evaluation approach was applied to evaluate the certainty of evidence for each outcome. Data were analyzed from April 6 to May 25, 2024.
Main outcomes and measures: School grades, school dropout, school absenteeism, grade retention, high school completion, university enrollment, postsecondary degree attainment, and unemployment.
Results: Sixty-three studies including 438 329 individuals proved eligible for analysis. Moderate-certainty evidence showed cannabis use during adolescence and young adulthood was probably associated with lower school grades (odds ratio [OR], 0.61 [95% CI, 0.52-0.71] for grade B and above); less likelihood of high school completion (OR, 0.50 [95% CI, 0.33-0.76]), university enrollment (OR, 0.72 [95% CI, 0.60-0.87]), and postsecondary degree attainment (OR, 0.69 [95% CI, 0.62-0.77]); and increased school dropout rate (OR, 2.19 [95% CI, 1.73-2.78]) and school absenteeism (OR, 2.31 [95% CI, 1.76-3.03]). Absolute risk effects ranged from 7% to 14%. Low-certainty evidence suggested that cannabis use may be associated with increased unemployment (OR, 1.50 [95% CI, 1.15-1.96]), with an absolute risk increase of 9%. Subgroup analyses with moderate credibility showed worse academic outcomes for frequent cannabis users and for students who began cannabis use earlier.
Conclusions and relevance: Cannabis use during adolescence and young adulthood was probably associated with increases in school absenteeism and dropout; reduced likelihood of obtaining high academic grades, graduating high school, enrolling in university, and postsecondary degree attainment; and perhaps increased unemployment. Further research is needed to identify interventions and policies that mitigate upstream and downstream factors associated with early cannabis exposure.
Importance: The multifaceted nature of screen use has been largely overlooked in favor of a simplistic unidimensional measure of overall screen time when evaluating the benefits and risks of screen use to early childhood development.
Objective: To conduct a systematic review and meta-analysis to examine associations of screen use contexts in early childhood with cognitive and psychosocial outcomes.
Data sources: PsycINFO, Embase, MEDLINE Ovid, ProQuest, CINAHL, Web of Science, and Scopus were searched from inception to December 31, 2023.
Study selection: A total of 7441 studies were initially identified. Studies were included if they examined associations between a contextual factor of screen use among children aged 0 to 5.99 years and cognitive or psychosocial development. Observational, experimental, and randomized clinical trial study designs were included.
Data extraction and synthesis: All studies were independently screened in duplicate following PRISMA guidelines. Effect sizes of associations (r) from observational studies were pooled using random-effects 3-level meta-analyses. The remaining study designs were narratively synthesized.
Main outcomes and measures: Screen use contexts included content (child directed and age inappropriate), type (program viewing and game or app use), co-use (or solo use), background television, caregiver screen use during child routines, and purpose. Outcomes were cognitive (executive functioning, language, and academic skills) or psychosocial (internalizing and externalizing behavior problems and socioemotional competence).
Results: Overall, 100 studies (176 742 participants) were included, and of these, 64 observational studies (pooled sample sizes ranging from 711 to 69 232) were included in meta-analyses. Program viewing (n = 14; k = 48; r, -0.16; 95% CI, -0.24 to -0.08) and background television (n = 8; k = 18; r, -0.10; 95% CI, -0.18 to -0.02) were negatively associated with cognitive outcomes, while program viewing (n = 6; k = 31; r, -0.04; 95% CI, -0.07 to -0.01), age-inappropriate content (n = 9; k = 36; r, -0.11; 95% CI, -0.17 to -0.04), and caregiver screen use during routines (n = 6; k = 14; r, -0.11; 95% CI, -0.20 to -0.03) were negatively associated with psychosocial outcomes. Co-use was positively associated with cognitive outcomes (n = 8; k = 28; r, 0.14; 95% CI, 0.03 to 0.25).
Conclusions and relevance: Findings show small to moderate effect sizes that highlight the need to consider screen use contexts when making recommendations for families, clinicians, and educators beyond screen time limits; including encouraging intentional and productive screen use, age-appropriate content, and co-use with caregivers.