Okamoto T, Hatakeyama S, Imai A, et al. - Researchers tried to find out if and how serum serotonin (5-HT) levels were associated with overactive bladder (OAB) in a community-dwelling population. A cross-sectional study was conducted to examine a total of 1,024 individuals (394 men and 630) in the Iwaki Health Promotion Project in 2015 in Hirosaki, Japan. Applying the overactive bladder symptom score, OAB was analyzed. Furthermore, serum 5-HT levels, laboratory data, and comorbidities of each individuals were measured. Utilizing the center for epidemiologic studies depression scale, individuals’ mental health status was tested. Via multivariable logistic regression analysis, the relationship of serum 5-HT levels and OAB was investigated. It was indicated that lower serum 5-HT levels could independently be correlated with the presence of OAB. Future research is required to evaluate a possible causal association between serum 5-HT levels and OAB.