The prevalence of ความรู้สึกเป็นสุข (euphoria) in AD across the 18 studies reporting on 5,488 persons ranged from 0.5% to 20%. The overall pooled prevalence of ความรู้สึกเป็นสุข (euphoria) was 7% (95% CI 5–9%) และ there was a high level ความไม่เหมือนกัน (heterogeneity) between studies (Supplementary Fig. 5). We performed meta-regression analyses, which demonstrated that factors of study setting (p = 0.039), และ age (p = 0.042) might explain some of the variance across studies (Table 1).