PURPOSE: Intensive care unit (ICU) mortality has decreased, highlighting improved patient outcomes. However, other critical factors affect post-ICU survival, including lasting physical, cognitive, and psychological challenges termed postintensive care syndrome (PICS), encompassing depression, anxiety, and posttraumatic stress disorder (PTSD). The prevalence of these conditions among ICU survivors is high and potentially linked to ICU treatment. This study aims to understand these factors using Taiwan's National Health Insurance Research Database (NHIRD), exploring their impact on mortality and readmission rates post-ICU discharge. METHODS: The National Health Insurance (NHI) program in Taiwan, implemented in 1995, provides healthcare for nearly all residents. Its research arm, NHIRD, contains comprehensive medical data for nationwide studies. This research focuses on ICU patients with specific conditions from 2010 to 2018, using ICD codes for diagnosis. Statistical analyses include Cox proportional hazard models and logistic regression, aiming to assess the incidence and risks of anxiety/depression/PTSD. RESULTS: ICU patients showed a higher risk of anxiety/depression/PTSD compared to non-ICU patients (adjusted HR = 1.17), with similar trends for anxiety and depression. Females, younger patients, those with higher CCI scores, on mechanical ventilators, and more extended hospital stays had increased odds of anxiety/depression/PTSD. ICU patients with anxiety/depression/PTSD faced increased risks of death and re-admission, especially among older males with comorbidities. CONCLUSION: This study discovered higher anxiety and depression rates post-ICU compared to general ward patients, particularly among younger individuals, females, and those with longer hospital stays. Factors such as higher comorbidity scores and mechanical ventilation use were linked to lower odds. Addressing mental health postdischarge is crucial, especially for at-risk groups.