Gender differences in depression, anxiety, and quality of life in Parkinson's disease before and after deep brain stimulation surgery: a multicentre cohort study.

Background: Disproportionately fewer females with Parkinson's disease (PD) undergo deep brain stimulation surgery (DBS). Some data show worse depression, anxiety, and quality of life (QOL) in females with PD. Investigations into these gender disparities, or the effect of DBS on these non-motor symptoms, remain limited. Methods: 61 PD patients across seven UK DBS centres were recruited for the Clinical Response of Impulsive behaviours to deep brain Stimulation in PD (CRISP) prospective cohort study. Questionnaires measured primary outcomes of depression (Patient Health Questionnaire-9), anxiety (Generalised Anxiety Disorder-7) and QOL (Parkinson's Disease Questionnaire-39) before and 6 months after bilateral subthalamic nucleus DBS, and secondary outcomes of predictors of postoperative changes in mood. Results: Females were disproportionately under-referred for DBS (28% of cohort). Baseline depression and anxiety were similar between genders. While DBS significantly improved overall anxiety (p<0.001), females reported significantly more postoperative anxiety than males (median score 7 vs 1.5, Cohen's d=0.33, p=0.009). Postoperatively, only males experienced a significant reduction in moderate depression, by 29% (p=0.004) (12% in females). QOL improved significantly by similar proportions, thus significantly worse QOL in females preoperatively was sustained as 9.12% worse postoperatively (Cohen's d=0.75, p=0.02). Preoperatively, females reported significantly worse mobility, social support, and pain; postoperatively, the significant difference in mobility was sustained. Longer PD duration, worse QOL, and mobility predicted postoperative depression (R2 =0.156, p=0.003), while female gender and reduced social support predicted postoperative anxiety (R2=0.23, p<0.001). Conclusions: DBS showed clinical efficacy for non-motor PD symptoms across genders, evidencing the need to close the gender gap in DBS. Analysis by gender highlighted significant disparities and postoperative predictors that provide impetus for tailored DBS counselling.