Systematic review of randomized clinical trials testing a pharmacological treatment in adults with autism spectrum disorder

Abstract Introduction: Autism Spectrum Disorder (ASD) affects 1 in 68 newborns. ASD is a neurodevelopmental condition characterized by deficits in social interaction, communication, and presence of restricted and repetitive interests. Despite this high prevalence and burden, there is no approved treatment for ASD’ core symptoms. Objective: This systematic review, using a rigorous methodological design, attempts to collect all clinical trials in adults with ASD have been published. Methods: To ensure the retrieval of a maximum of articles, the systematic review used the databases Medline and Scopus. Retrieved manuscripts were evaluated reading the title, keywords, and abstract. CONSORT guidelines were used to evaluate the quality of included manuscripts (0-100% scale). Results: A total of 17/86 (20%) clinical trials were selected with an average score of 70% in CONSORT. In general, sample sizes were low, ranged from 30 (single-center studies) to 115 participants (multiple inclusion sites), and an average age of 27 years-old. Pharmacological treatments studied were for improving a) social interaction and attachment (propranolol, oxytocin); b) cognitive abilities (cannabidiol); c) behavior (naltrexone, vasopressin V1a antagonists, dextromethorphan, quinidine, agomelatine, and citalopram); d) facial expression and emotion recognition (citalopram oxytocin, and V1a receptor antagonist). Conclusion: regardless the methodological quality, there are few studies in this field with a low number of participants. Furthermore, different designs and measures to assess efficacy are used, and that avoids comparisons between them. Therefore, it is necessary to raise awareness in this field, and increase the number of clinical trials in the future with long-term side-effect monitoring.