Sex differences in the severity of non-motor symptoms in Parkinson’s disease: a systematic review and meta-analysis

Non-motor symptoms (NMS) in Parkinson's Disease (PD) encompass a variety of symptoms which may differ in terms of presentation and severity according to gender. However, literature evidences are often conflicting due to the use of different instruments. The Non-Motor Symptoms Scale (NMSS) is a validated tool widely used to holistically assess NMSs in PD. We aimed to summarize available data on gender differences in NMS severity in PD using the NMSS. A literature review has been performed in the PubMed and Scopus databases up to 1st February 2025. A random effect model was used to report pooled effects. Nine full text articles have been included in the analysis, pooling the data of 4352 PD patients N = 2453 (58%) men. Women showed higher symptoms severity in mood/cognition whereas higher severity in the sexual domain was found in men. These findings highlight the need for a specific gender-related approach in PD.