Childhood abuse and neglect can increase the risk of developing post-traumatic stress disorder (PTSD) and psychosis later in life. However, it's unclear how PTSD and psychotic symptoms are related. This study explored whether having PTSD, including a more severe form called complex PTSD, is linked to the severity of psychotic symptoms in people who experienced childhood trauma. Researchers used an international trauma questionnaire to categorize 2,675 participants from the UK and South Korea into groups with PTSD or complex PTSD. The study found that only complex PTSD was significantly associated with more severe psychotic symptoms. Regular PTSD and those without PTSD did not show this link. These findings highlight the importance of health systems assessing individuals with a history of childhood trauma for complex PTSD and providing appropriate treatment. Additionally, those with complex PTSD should be evaluated for psychotic symptoms, and preventive measures should be taken to reduce the risk of developing psychosis. Further research should investigate whether treating complex PTSD can lower this risk.