Time-Dependent\nIntrinsic Correlation Analysis Reveals\nPositive Relationship between Drug Types in Wastewater: Antidepressants\nvs Illicit Drugs and Analgesics vs Antibiotics/Antivirals

The connection between mental health and illicit substance\nuse\ndisorder is intricate and poorly understood but may potentially be\nunraveled by examining residues of antidepressants and illicit drugs\nthrough wastewater-based epidemiology (WBE). In this study, we assessed\ntime-dependent intrinsic correlations (TDIC) between the concentrations\nof antidepressants and illicit drugs and their metabolites in untreated\nsewage samples during three sampling campaigns, from September 2022\nto May 2024. Notable positive correlations (+medium in 2022; +weak\nin 2023; +medium in 2024) were observed between illicit drugs (e.g.,\nmethamphetamine, cocaine, and its benzoylecgonine metabolite) and\nbupropion (an antidepressant). For other psychoactive drugs examined\n(citalopram, venlafaxine, and its metabolite desvenlafaxine), +medium\ncorrelations were observed with illicit drugs in the 2023 and 2024\nsampling campaigns. This is the first time WBE demonstrates the interconnection\nbetween prescription psychoactive drugs, such as antidepressants,\nand illicit drugs, underscoring TDIC’s strength in extracting\ninformation from complementary data. We applied similar data analytics\nusing residues of antivirals and antibiotics in untreated sewage and\ntheir correlation with acetaminophen; the expected results were obtained.\nTDIC between acetaminophen and antibiotics showed a strong correlation\nduring the whole sampling event, supporting the applicability of TDIC\nin WBE research.