Psychosis-related trauma is a prevalent condition that significantly impacts patients and often leads to an increased reliance on psychiatric nursing services. This study aimed to provide a deeper understanding of the complex relationship between cumulative trauma and the severity of psychosis symptoms among patients experiencing psychosis. Utilizing a cross-sectional research design, data were collected from 76 community-dwelling patients recruited. Patients' sociodemographic and clinical data, Cumulative Trauma Measure scores, and psychosis symptom severity scale scores were collected. A significant difference was observed between collective identity trauma and the presence of hallucinations and abnormal psychomotor behavior (Z = 4.1 and 2.69, respectively). Significant differences were also observed between role identity trauma and the presence of delusions and abnormal psychomotor behavior (Z = 3.86 and 2.06, respectively); attachment trauma and the presence of hallucinations, abnormal psychomotor behavior, and mania (Z = 2.16, 2.12, and 2.11, respectively); and survival trauma and the presence of disorganized speech (Z = 2.61). Moreover, there was a significant difference regarding secondary trauma and the presence of hallucinations, delusions, disorganized speech, abnormal psychomotor behavior, depression, and mania (Z = 4.29, 2.15, 2.11, 2.12, 4.42, and 3.39, respectively). In conclusion, total cumulative trauma explained 44.2 %, 25.8 %, 24.7 %, 16.2 %, 13.6 %, and 13.2 % of the severity of delusion, hallucination, depression, mania, abnormal psychomotor behavior, and disorganized speech, respectively, among patients experiencing psychosis. Implication for nursing practice, by recognizing the nuanced interplay between cumulative trauma and diverse manifestations of psychosis symptoms, nursing professionals can tailor their approaches to provide more holistic and patient-centered care that may significantly contribute to improved patient outcomes and the overall well-being of individuals navigating the complex landscape of psychosis-related trauma.