Background <p>According to the World Health Organization, approximately one in eight people is diagnosed with mental disorders globally. Patient-reported outcomes and quality of life assessments are essential tools for evaluating patient outcomes. This study aimed to identify, characterize, and summarize the literature focusing on quality of life or patient-reported outcomes among patients with mental disorders in the Kingdom of Saudi Arabia undergoing pharmacological treatment.</p> Methods <p>This systematic review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 item checklist applicable for Systematic reviews. Searches were run in the following databases: PubMed, MEDLINE via Ovid, MEDLINE via EBSCO, and ProQuest. Databases were searched from January 1, 2000, to July 31, 2025.</p> Results <p>Ten articles that explored the quality of life of patients undergoing mental disorders treatment in the Kingdom of Saudi Arabia since 2000 met the inclusion criteria. A total of 3,773&#xa0;patients included, and fifteen different quality of life questionnaires and patient-reported outcome measures were used. One-third of the reviewed articles used the Morisky Medication Adherence Scale (MMAS) and consistently reported low to moderate levels of adherence.</p> Conclusions <p>This study highlights the need for further research in the mental health field, with a focus on enhancing patients’ quality of life and reporting outcomes.</p>