The treatment of mental illness is often done on a trial-and-error basis and achieving therapeutic benefits from a medication is not always guaranteed. Pharmacogenomics explores the role of gene-gene interactions and interindividual responses to a drug and may be promising in the guidance of pharmacotherapeutic options. In the present study, the impact of pharmacogenomic testing in management of mental health medication was investigated. Participants were identified at a local outpatient mental health facility through convenience sampling. Retrospective chart review included medication history, adverse drug reactions, pharmacogenomic history, and demographic data including insurance coverage. Chart review focused on six months pre- and post-pharmacogenomic for a comparison with the patient serving as their own control. Results indicate a high incidence of alterations in two specific cytochrome enzymes, CYP2D6 and CYP2C19. In total, 82% of the sample had variations with CYP2D6, while 64% of individuals had variations with CYP2C19. In total, 91% of patients tested received Medicaid or Medicare. Post-pharmacogenomic testing, all patient drug regimens were modified, and all reported less adverse side effects. Moreover, advanced practice nurse providers educated patients about the availability of genetic testing, initiated testing and provided care based on findings. These results demonstrate the utility of genetic testing in the realm of mental health. Future directions involve further exploring the benefits of pharmacogenomic testing in this vulnerable population.