Efficacy of Antioxidant-Based Pharmacological Therapies in Autism Spectrum Disorder: A Systematic Review

Purpose: Autism Spectrum Disorder (ASD) is a heterogeneous neurodevelopmental condition characterized by persistent deficits in social interaction and communication. This study aimed to evaluate the efficacy of antioxidant-based pharmacological therapies for psychiatric symptoms in patients with ASD. Methods: A systematic review was conducted using four databases: PubMed, Scopus, ClinicalTrials.gov and Cochrane - Ovid. 20 studies were included. Risk of bias assessment was performed using the Cochrane Risk-of-Bias tool for randomized trials. A descriptive analysis synthesized the main findings. A qualitative value was given to each antioxidant therapy according to its effect on every symptom (improved, not improved or no information), data was visually reported using ChatGPT 4.0 and Google Collab. PROSPERO ID: CRD42023490581. Results: There was a heterogeneous response to antioxidant therapies for ASD symptoms. The use of sulforaphane reported improvement in irritability, stereotypic/repetitive behavior, social cognition/interaction, social communication, hyperactivity and lethargy. Similarly, N-Acetylcysteine evidenced improvement in terms of irritability, stereotypic/repetitive behavior, social cognition and hyperactivity. L-Carnosine improved social cognition and communication, omega-3/omega-6 fatty acids improved social cognition, coenzyme q-10 showed improvement in sleep disorders, and glutathione in repetitive behaviors and irritability. Conclusion: Antioxidant-based pharmacological therapy evidenced contrasting responses to a variety of core symptoms in ASD. Despite significant evidence of improvement in some ASD symptom scales, there is still a lack of evidence to justify the use of antioxidant therapies as monotherapy in individuals with ASD.