Table 2: Characteristics and main results from systematic reviews included .

ASD = autism spectrum disorders; *GRADE = Grading of Recommendations Assessment, Development and Evaluation. Tool used for assessing the quality of the body of the current evidence. High quality: low probability that further studies will change the confidence regarding the existing evidence. Moderate quality: some probability that further studies will change the confidence regarding the existing evidence. Low quality: high probability that further studies will change the confidence regarding the existing evidence. Very low quality: there is much uncertainty about the information, precluding any valid interpretation.²⁶