RESUMO
WHAT IS KNOWN AND OBJECTIVE: Attention-deficit hyperactivity disorder (ADHD) symptoms usually impairs academic achievement and can trigger the onset of medication. Methylphenidate is a drug widely prescribed to treat ADHD. However, systematic reviews of randomized clinical trials suggest that it does not lead to great improvements in academic performance. Thus, we aimed to evaluate the evidence on the "real-world" effectiveness of methylphenidate in improving the academic achievement of ADHD students. METHODS: We conducted a systematic review of observational studies retrieved from five electronic databases, besides a manual search and search in grey literature. Studies evaluating treatment with methylphenidate compared to no treatment or other pharmacological/non-pharmacological alternatives used in ADHD were included. The risk of bias of the selected studies was assessed using adapted versions of the Newcastle-Ottawa Scale. RESULTS AND DISCUSSION: Nine studies (from ten reports) were included in the review: four cohorts, two before-and-after designs and three cross-sectional studies. They involved 12,269 children and adolescents aged 6-18 years. The doses of methylphenidate ranged from 10 to 72 mg/day, and the duration of the treatment from 2.6 months to 4.25 years. Five of these studies concluded that methylphenidate improves academic performance. However, three of the four lowest-bias risk studies concluded that the drug is ineffective. Five studies assessed the long-term use of methylphenidate, and four of them concluded that it does not result in better outcomes in the school setting. Most included studies had considerable limitations and significant heterogeneity regarding methodological design and academic performance measurement criteria. WHAT IS NEW AND CONCLUSION: Although some studies indicate that the short-term use of methylphenidate may improve outcomes in the school environment, the available evidence does not support the establishment of adequate conclusions about the real benefits of methylphenidate in the academic improvement of ADHD students.