Gender disparity and abuse in functional movement disorders: a multi-center case-control study

Background: To determine gender differences in rates of sexual and physical abuse in functional movement disorders compared to controls and evaluate if the gender disparity of functional movement disorders is associated with abuse history. Methods: We performed a retrospective case-control study of self-reported trauma data from 696 patients (512 women) with functional movement disorders from six clinical sites compared to 141 controls (98 women) and population data. Chi-square was used to assess gender and disorder associations; logistic regression was used to model additive effects of abuse and calculate the attributable fraction of abuse to disorder prevalence. Results: Higher rates of sexual abuse were reported by women (35.3%) and men (11.5%) with functional movement disorders compared to controls (10.6% of women; 5.6% of men). History of sexual abuse increased the likelihood of functional movement disorders among women by an odds ratio of 4.57 (95% confidence interval 2.31–9.07; p < 0.0001) and physical abuse by an odds ratio of 2.80 (95% confidence interval 1.53–5.12; p = 0.0007). Population attributable fraction of childhood sexual abuse to functional movement disorders in women was 0.12 (0.05–0.19). No statistically significant associations were found in men, but our cohort of men was underpowered despite including multiple sites. Conclusions: Our study suggests that violence against women may account for some of the gender disparity in rates of functional movement disorders. Most people with functional movement disorders do not report a history of abuse, so it remains just one among many relevant risk factors to consider.