AbstractRapid eye movement sleep behavior disorder (RBD) is a common prodromic non-motor symptom of Parkinson’s disease (PD). Only few studies have evaluated the personality of RBD patients with conflicting results. Aim of the study was to evaluate the frequency of Personality Disorders (PeDs)in RBD. RBD patients, PD patients and healthy controls (HC) were enrolled. All the enrolled subjects underwent a full neurological examination. Motor symptoms were evaluated with the UPDRS-Motor Examination. PeDs were assessed with the Structured Clinical Interview for DSM-IV Personality Disorders (SCID-II). Twenty-nine RBD patients [14 men (48.3%); mean age 55.6 ± 11.1], 30 PD patients [17 men (56.7%); mean age 65.7 ± 10.7] and 30 HC [12 men (40%); mean age 65.7 ± 5.4] were enrolled in the study. PD patients had a disease duration of 4.5 ± 4.6 and presented a mean UPDRS-ME score of 26.7 ± 9.4. The most frequent PeDs was the Obsessive–Compulsive one (OCPeD); OCPeD was significantly more frequent in RBD (55.2%) patients than HC (13.3%; p-value < 0.001). No significant differences were found comparing the frequency of OCPeD in RBD patients to that in PD. In the present study, the prevalence of OCPeD in RBD patients was close to that reported in PD patients. Our data could suggest the existence of a common disease-specific RBD-PD personality profile.