The Future of Oncology in Psychiatric Medications

Recent years have provided numerous reports on the mechanisms of action of psychiatric medications (antidepressants, antipsychotics, mood stabilizers, and antidementia drugs) that directly inhibit the growth of cancer cells, as well as on their indirect effects on the psyche and immune system, and their supportive effects on chemotherapeutic agents. The mechanisms of the anticancer activity of psychiatric drugs include inhibition of dopamine and N-methyl-D-aspartate receptors that work via signaling pathways (PI3K/AKT/mTOR/NF-κB, ERK, Wnt/ß-catenin, and bcl2), metabolic pathways (ornithine decarboxylase, intracellular cholesterol transport, lysosomal enzymes, and glycolysis), autophagy, Ca²⁺-dependent signaling cascades, and various other proteins (actin-related protein complex, sirtuin 1, p21, p53, etc.). The anticancer potential of psychiatric drugs seems to be extremely broad, and the most extensive anticancer literature has been reported on antidepressants (fluoxetine, amitriptyline, imipramine, mirtazapine, and St John's Wort) and antipsychotics (chlorpromazine, pimozide, thioridazine, and trifluoperazine). Among mood stabilizers, lithium and valproates have the largest body of literature. Among antidementia drugs, memantine has documented anticancer effects, while there is limited evidence for galantamine. Of the new psychiatric substances, the antipsychotic drug brexpiprazole and the antidepressant vortioxetine have a very interesting body of literature regarding glioblastoma, based on in vitro and in vivo animal survival studies. Their use in brain tumors and metastases is particularly compelling, as these substances readily cross the blood-brain barrier (BBB). Moreover, the synergistic effect of psychiatric drugs with traditional cancer treatment seems to be extremely important in the fight against chemo- and radio-resistance of tumors. Although there are some studies describing the possible carcinogenic effects of psychiatric drugs in animals, the anticancer effect seems to be extremely significant, especially in combination treatment with radio/chemotherapy. The emerging evidence supporting the anticancer properties of psychiatric drugs presents an exciting frontier in oncology. The anticancer properties of psychiatric drugs may prove particularly useful in the period between chemotherapy and radiotherapy sessions to maintain the tumor-inhibitory effect. While further research is necessary to elucidate the mechanisms, clinical implications, dose-dependence of the effect, and clear guidelines for the use of psychiatric medications in cancer therapy, the potential for these commonly prescribed medications to contribute to cancer treatment enhances their value in the management of patients facing the dual challenges of mental health and cancer.