Whether the effects of cannabis use on brain function persist or recover following abstinence remains unclear. Therefore, using meta-analytic techniques, we examined whether functional alterations measured using fMRI persist in cannabis users abstinent for over 25 days (or 600 h) as evidence suggests that the effects on cognitive performance no longer persist beyond this period. Systematic literature search identified 20 studies, of which, 12 examined current cannabis users (CCU) (361 CCU versus 394 non-cannabis using controls (NU)) and 3 examined abstinent cannabis users (ACU) in 5 separate comparisons (98 ACU versus 106 NU). Studies in ACU were carried out in adolescents and suggest significantly greater activation in components of the central executive and default mode networks in adolescent ACU compared to NU. While this evidence is to be interpreted with caution because studies were carried out in overlapping samples, they indicate a pressing need for independent confirmation whether certain neurofunctional alterations in adolescent cannabis users may persist even after cannabis and its metabolites are likely to have left their bodies.

大麻使用对大脑功能的影响是否会在禁欲后持续或恢复仍不清楚。因此，使用荟萃分析技术，我们检查了使用 fMRI 测量的功能改变是否在大麻使用者禁欲超过 25 天（或 600 小时）中持续存在，因为有证据表明，对认知表现的影响在此期间不再持续存在。系统文献检索确定了 20 项研究，其中 12 项检查了当前大麻使用者（CCU）（361 名 CCU 对 394 名使用对照的非大麻使用者（NU））和 3 项检查了戒断大麻使用者（ACU）的 5 次单独比较（98 名 ACU 对 106努）。ACU 的研究是在青少年中进行的，表明与 NU 相比，青少年 ACU 的中央执行和默认模式网络的组件激活显着更大。