Substance abuse and academic performance among university students: systematic review and meta-analysis

Background. Substance abuse is a widespread concern among young adults and is particularly significant among college students. Substance abuse in this population is linked to numerous academic, physical, mental, and social difficulties. This systematic review and metanalysis explores whether there is an effect of the illegal drug and alcohol consumption behaviors on academic achievement among university students. Methods. The databases searched were MEDLINE, CINHAL, Scopus, ERIC, and PROSPERO, updated in January 2025. The risk of bias was assessed using the Edward score. We used a random-effects model. The protocol of this review was registered in the Open Science Framework. Results. The systematic review included 21 studies, while the meta-analysis included four studies. In a sample of 1,219 subjects in the control group and 350 illegal drug consumers, there is a negative and significant effect of drug consumption on academic achievement [SMD = − 0.61 (95% CI − 0.84 to − 0.38; p = 0.008). In a subgroup analysis, a sample of 2,479 subjects in the control group and 7,134 alcohol consumers, there is a small effect of alcohol consumption on academic achievement [SMD = − 0.24 (95% CI -0.51 to 0.04; p = 0.073). Conclusions. This systematic review provides quantitative evidence on the relationship between legal and illegal use of drugs among university students and academic achievement. Specifically, we found a significant medium effect of substance abuse in general and a small effect for alcohol consumption on academic achievement.