Evaluation of eight psychoactive drugs used in Chinese cities by wastewater-based epidemiology

With rapid economic development, an increasing number of people suffer from mental health diseases, which are gradually receiving the attention of society. However, basic data from surveys of mental disorders are limited. Composite influent samples were collected from 26 wastewater treatment plants in 23 major cities in China. The concentrations of the psychoactive drugs diphenhydramine, fluoxetine, doxepin, imipramine, sulpiride, zolpidem, carbamazepine, and flunitrazepam in the wastewater were determined. The detection frequency of diphenhydramine, sulpiride, and carbamazepine was close to 100 %, whereas that of the compounds was lower than 35 %. Carbamazepine had the highest mean consumption (31.1 mg/d/1000 people), followed by diphenhydramine (10.4 mg/d/1000 people) and sulpiride (11.3 mg/d/1000 people). Wastewater-based epidemiology (WBE) estimates of the average use of the three drugs were lower than those from the drug statistics data. Consumption of diphenhydramine in northern China was higher than that in southern China. A correlation analysis of psychotropic and illicit drugs revealed a correlation between sulpiride and heroin use, which may be related to the adverse effects of sulpiride treatment after heroin withdrawal. Psychotropic drug use is associated with both economic and social factors. We found associations between the use of the three drugs and age, occupation, and obesity, which are risk factors for mental disorders. The results showed that the monitoring of psychotropic drug using WBE has a certain reference value for public health care and for improving the understanding of mental disorders.