Substance Abuse and Cognitive Decline: The Critical Role of Tau Protein as a Potential Biomarker
International Journal of Molecular Sciences – August 07, 2025
Source: OpenAlex
Summary
Surprisingly, certain psychedelics like psilocybin can decrease Tau protein phosphorylation and aid cognitive restoration in animal models. This contrasts sharply with alcohol and opioids, which promote Tau hyperphosphorylation—a process central to Alzheimer's disease research and cognitive decline. Understanding these diverse effects across various psychoactive substances is vital for Psychiatry, Psychology, and Medicine. Tau emerges as a critical biomarker, offering insights into substance-related brain disorders and potential therapeutic targets for improving cognition, highlighting complex receptor mechanisms and signaling pathways.
Abstract
Tau protein is essential for the structural stability of neurons, particularly through its role in microtubule assembly and axonal transport. However, when abnormally hyperphosphorylated or cleaved, Tau can aggregate into insoluble forms that disrupt neuronal function, contributing to the pathogenesis of neurodegenerative diseases such as Alzheimer’s disease (AD). Emerging evidence suggests that similar Tau-related alterations may occur in individuals with chronic exposure to psychoactive substances. This review compiles experimental, clinical, and postmortem findings that collectively indicate a substance-specific influence on Tau dynamics. Alcohol and opioids, for instance, promote Tau hyperphosphorylation and fragmentation through the activation of kinases such as GSK-3β and CDK5, as well as proteases like caspase-3, leading to neuroinflammation and microglial activation. Stimulants and dissociatives disrupt insulin signaling, increase oxidative stress, and impair endosomal trafficking, all of which can exacerbate Tau pathology. In contrast, cannabinoids and psychedelics may exert protective effects by modulating kinase activity, reducing inflammation, or enhancing neuroplasticity. Psychedelic compounds such as psilocybin and harmine have been demonstrated to decrease Tau phosphorylation and facilitate cognitive restoration in animal models. Although the molecular mechanisms differ across substances, Tau consistently emerges as a convergent target altered in substance-related cognitive disorders. Understanding these pathways may provide not only mechanistic insights into drug-induced neurotoxicity but also identify Tau as a valuable biomarker and potential therapeutic target for the prevention or treatment of cognitive decline associated with substance use.