BackgroundChildhood trauma may contribute to poorer premorbid social and academic adjustment which may be a risk factor for schizophrenia.AimWe explored the relationship between premorbid adjustment and childhood trauma, timing of childhood trauma’s moderating role as well as the association of clinical and treatment-related confounders with premorbid adjustment.SettingWe conducted a secondary analysis in 111 patients with first-episode schizophrenia (FES) disorders that formed part of two parent studies, EONKCS study (n =73) and the Shared Roots study (n =38).MethodsType of childhood trauma was assessed with the Childhood Trauma Questionnaire, short-form and premorbid adjustment using the Premorbid Adjustment Scale. Timing of childhood trauma was assessed using the Life Events Checklist and life events timeline. Linear regression analyses were used to assess the moderating effect of timing of childhood trauma. Clinical and treatment-related confounders were entered into sequential hierarchical regression models to identify independent predictors of premorbid adjustment across key life stages.ResultsChildhood physical neglect was associated with poorer premorbid academic functioning during childhood and early adolescence, and poorer premorbid social functioning during early and late adolescence. By hierarchical regression modelling (r2 = 0.13), higher physical neglect subscale scores (p = 0.011) independently predicted poorer premorbid social adjustment during early adolescence. Timing of childhood trauma did not moderate the relationship between childhood trauma and premorbid functioning.ConclusionIn patients with FES, childhood physical neglect may contribute to poorer premorbid social functioning during early adolescence. This may provide us with an opportunity to identify and treat at-risk individuals earlier.