Exploring Cancer-Related Therapeutic Roles of Psychiatric Medications: Mechanistic Insights and Clinical Relevance

Cancer continues to impose a substantial global health burden, while the development of novel anticancer agents remains costly, time-consuming, and inefficient. Drug repurposing has therefore emerged as a strategic alternative, enabling the identification of new oncological applications for established drugs with known pharmacokinetic and safety profiles. Psychiatric medications, including antidepressants, antipsychotics, mood stabilizers, and monoamine oxidase inhibitors, have attracted increasing interest due to accumulating evidence of their anticancer potential. Preclinical and translational studies demonstrate that several psychiatric drugs exert antineoplastic effects by modulating key molecular pathways involved in tumour growth and progression, such as apoptosis, autophagy, epigenetic regulation, immune and inflammatory signalling, angiogenesis, and cellular metabolism. Agents such as valproic acid, selective serotonin reuptake inhibitors, thioridazine, and penfluridol have shown significant antiproliferative and pro-apoptotic activity across diverse cancer models. In parallel, depression is highly prevalent among patients with cancer and is associated with impaired treatment adherence, reduced quality of life, and poorer clinical outcomes, highlighting the dual relevance of psychiatric drugs in oncology. This review synthesizes current evidence on the anticancer mechanisms of psychiatric medications, evaluates their therapeutic implications in cancer-associated depression, and discusses safety considerations, drug–drug interactions, and challenges related to clinical translation. Overall, psychiatric drug repurposing represents a promising, cost-effective strategy that may complement conventional anticancer therapies and contribute to more comprehensive, patient-centred cancer management. Further well-designed clinical trials are required to establish efficacy and define optimal therapeutic roles.