The impact of psychological trauma on weight loss, psychosocial functioning, and psychopathology in bariatric and metabolic surgery candidates: a systematic review

Up to 22% of bariatric and metabolic surgery (BMS) candidates experience trauma or stressor-related symptoms and/or diagnoses (trauma-related distress), such as post-traumatic stress disorder (PTSD), yet research assessing their impact on surgical outcomes remains limited. To our knowledge, this is the first systematic review examining how presurgical trauma-related distress affects postsurgical BMS outcomes. Five electronic databases and five grey literature sources were searched from inception to April 2025 for quantitative studies of adults undergoing BMS with current symptoms or diagnoses of trauma-related distress. Studies had to report associations between presurgical trauma-related distress and postsurgical outcomes. The Newcastle-Ottawa Scale was used to assess study quality. Narrative synthesis and vote counting by direction of effect was utilized. Nine observational studies (n = 5457) met inclusion criteria, ranging from poor to fair quality. PTSD was not statistically associated with postoperative weight loss in any study (n = 4). In one study, PTSD was associated with other mental health disorders, including major depressive disorder. Another study showed that people presenting with PTSD had worse mental health-related quality of life (QoL) than controls. Adjustment disorders showed no significant effect on postoperative weight loss (n = 1). Despite the high prevalence of trauma in this population, high-quality research on its impact on BMS outcomes is scarce, with methodological heterogeneity further limiting robust conclusions. The limited available evidence suggests PTSD and adjustment disorders do not significantly affect post-surgical weight loss, but QoL may be reduced in this population. Future research should employ standardized trauma measures, larger samples, and long-term follow-up to clarify how active trauma-related distress impacts BMS outcomes.