RESUMO
BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder associated with cognitive, social, and academic impairment. Neurotrophins, particularly brain-derived neurotrophic factor (BDNF), have been implicated in the pathophysiology of ADHD and response to stimulant treatment. This review aims to investigate the relationship between BDNF levels in ADHD before and after treatment with stimulants in childhood. METHODS: This systematic review followed PRISMA-P guidelines and included 19 studies from PubMed, EMBASE, Cochrane, Capes Periodic, and Lilacs databases. The studies were evaluated for risk of bias and level of evidence. RESULTS: There was no significant difference in peripheral BDNF levels in ADHD children before or after methylphenidate treatment. Additionally, there was no statistically significant difference in BDNF levels between children with ADHD and controls. DISCUSSION: Understanding the role of BDNF in ADHD may provide insight into the disorder's pathophysiology and facilitate the development of biological markers for clinical use. CONCLUSION: Our findings suggest that BDNF levels are not significantly affected by methylphenidate treatment in ADHD children and do not differ from controls. SYSTEMATIC REVIEW REGISTRATION: "Brain-derived neurotrophic factor (BDNF) levels in children and adolescents before and after stimulant use: a systematic review". Number CRD42021261519.