Developmental trauma in functional motor disorder: the mediating roles of affective symptoms and multimorbidity

Childhood trauma is common in functional motor disorder (FMD), but it is unclear whether specific trauma dimensions are differentially linked to symptom burden, and whether depression, anxiety, or multimorbidity can mediate these associations.

We conducted a cross-sectional case-control study including 322 patients with clinically definite FMD and 215 neurologically healthy controls, balanced with respect to age and sex. Six outcomes - motor symptom severity, cognitive complaints, depression, anxiety, fatigue, and pain - were jointly modeled using Bayesian multivariate regression with Childhood Trauma Questionnaire subscales as predictors. Bayesian structural equation modeling tested mediation by depression, anxiety, and multimorbidity.

In FMD, emotional abuse was the most consistent trauma correlate, associated with higher depression (β = 0.37, 95% CrI 0.22-0.51), anxiety (β = 0.32, 95% CrI 0.16-0.47), cognitive complaints (β = 0.27, 95% CrI 0.11-0.42), fatigue (β = 0.17, 95% CrI 0.03-0.32), and motor symptom severity (β = 0.15, 95% CrI 0.04-0.25). Mediation analyses indicated that affective symptoms fully accounted for trauma-symptom associations (indirect effect β = 0.42, 95% CrI 0.27-0.56). Multimorbidity was associated with more severe affective symptoms (β = 0.24, 95% CrI 0.12-0.37) and FMD symptoms (β = 0.24, 95% CrI 0.07-0.42) but did not mediate trauma-symptom relationships.

Emotional abuse is a key developmental risk factor for FMD, with its effects on symptom severity mediated by depression and anxiety. Multimorbidity increases symptom burden but is not a primary pathway linking trauma to FMD. Findings support routine trauma and affective symptom screening in FMD and targeted psychotherapeutic interventions.