To examine the prevalence of psychological trauma and its effect on 12-month weight change, eating disorder risk, and health-related quality of life (HRQOL), among individuals with class 3 obesity (BMI ≥40 kg/m ² ) attending an intensive multidisciplinary weight management program (WMP).

This retrospective cohort study included patients in a Sydney hospital-based WMP (2018–2021) who consulted a clinical psychologist. The Eating Disorder Examination Questionnaire-Short (EDE-QS), Kessler Psychological Distress Scale (K10), and 36-Item Short Form Survey (SF-36) were completed at baseline and 12 months. Mental and physical component summary (MCS and PCS) scores were derived from SF-36. History of trauma was extracted from clinical notes in electronic medical records.

Of 269 participants, 46.1 % (n = 124) reported previous psychological trauma. At baseline, participants with trauma had higher K10 and lower MCS scores than individuals without trauma. After 12 months, there were similar improvements in weight change, EDE-QS, K10, PCS and MCS scores, with no significant differences between participants with or without trauma. Presence of trauma was associated with baseline EDE-QS, K10 and MCS scores, but not with changes over 12 months.

There is a high prevalence of psychological trauma among individuals with class 3 obesity presenting to a multidisciplinary WMP. Similar 12-month weight loss and HRQOL improvements were observed among those with or without trauma when access to a mental healthcare professional was embedded within the team.