Finding into death of Catherine Ann Williamson

58y · Female·plastic bag asphyxia

Catherine Williamson, a 58-year-old voluntary psychiatric inpatient, died from plastic bag asphyxia at a private mental health facility. She had schizo-affective disorder and a history of suicide attempts. Despite returning from supervised leave on 10 September 2017, no physical search was performed. She obtained a plastic bag and shower cap, which were not adequately controlled as high-risk items. Overnight nursing observations failed to detect her death for several hours. The coroner found that adherence to proper observation practices (confirming signs of life) and timely implementation of updated observation policies would likely have prevented her death. Key clinical lessons include: risk assessment must be thorough and consistent; observation rounds must explicitly confirm vital signs; high-risk items must be strictly controlled; and policy changes must be rapidly communicated to clinical staff. The case highlights the tension between therapeutic milieu and safety in voluntary psychiatric admissions.