Exploring comorbidity patterns of psychosis-related post-traumatic stress disorder and depression symptoms in stabilised hospitalised schizophrenia patients and relationships with sleep quality and quality of life: a latent profile analysis

<b>Background:</b> Comorbidity symptoms of posttraumatic stress disorder (PTSD) and depression are common and debilitating in schizophrenia, yet their patterns of co-occurrence remain poorly understood. This study aimed to identify severity-based comorbidity profiles of psychosis-related PTSD (PR-PTSD) and depression symptoms in hospitalised patients with schizophrenia and to examine their associations with sleep quality and quality of life.<b>Methods:</b> We conducted a cross-sectional study of 482 stabilised inpatients with schizophrenia (PANSS total score < 60), assessing PR-PTSD symptoms (IES-R), depression symptoms (SDS), sleep quality (PSQI), and quality of life (SQLS). Latent profile analysis was used to identify comorbidity profiles based on scores for PR-PTSD (intrusion, avoidance, arousal) and depression. Multinomial logistic regression and analysis of variance (ANOVA) were employed to examine correlates of profile membership and compare differences in outcomes.<b>Results:</b> LPA revealed an optimal three-profile solution: 'Low PR-PTSD/Low Depression' (50.0%), 'Moderate PR-PTSD/Mild Depression' (42.3%), and 'High PR-PTSD/Moderate Depression' (7.7%). Multinomial logistic regression indicated that a history of coercive treatment and polypharmacy were significantly associated with membership in the high-symptom profile. A clear dose-response relationship was observed for sleep quality, which progressively worsened with increasing comorbidity severity across profiles (<i>p</i> < .001). However, the overall group difference in quality of life total scores did not reach statistical significance (<i>p</i> = .067).<b>Conclusion:</b> Comorbid symptoms of PR-PTSD and depression in schizophrenia manifest as parallel severity profiles rather than distinct symptom-dominant subtypes. Sleep quality is a key differentiating factor and a potent transdiagnostic target for intervention. These findings underscore the need for stratified care models that address clinical correlates of high symptom burden, such as iatrogenic trauma and polypharmacy, to improve outcomes in this vulnerable population.