The Flynn Effect (FE) among child and adolescent populations indicates that intelligence scores improve by about three points per decade. Using nine years of data from the National Database for Autism Research, this study examined whether general intelligence changed significantly for nine cohorts with autism spectrum disorder (ASD; N = 671). Analyses demonstrated a downward trend such that Cohen’s d from 1998 to 2006 was − 0.27. The mean IQ is 92.74 for years 1–3, 91.54 for years 4–6, and 87.34 for years 7–9, indicating a reverse FE of 5.4 points per decade. A linear regression revealed a significant negative FE comparable to the positive effect of age on IQ among those with ASD. Implications for research, practice, and law are discussed.

儿童和青少年群体的弗林效应 (FE) 表明，智力分数每十年提高约 3 分。本研究使用来自国家自闭症研究数据库的九年数据，检查了九个自闭症谱系障碍（ASD；N  = 671）队列的一般智力是否发生了显着变化。分析显示出下降趋势，因此从 1998 年到 2006 年，科恩的d为 - 0.27。第 1-3 年的平均智商为 92.74，第 4-6 年为 91.54，第 7-9 年为 87.34，表明每十年 5.4 点的反向 FE。线性回归显示显着的负 FE 与年龄对自闭症患者智商的积极影响相当。讨论了对研究、实践和法律的影响。