Social Anxiety Disorder (SAD) is a psychiatric co-morbidity commonly related to Parkinson's disease (PD). However, the real nature of this association is still unknown. The objective of the present study was to determine the prevalence of SAD in patients with a diagnosis of PD.

Eighty-seven consecutive patients with a diagnosis of PD and no associated dementia were evaluated at a movement disorder outpatient clinic. The patients were independently interviewed using the SCID-IV for DSM-IV.

Patient age ranged from 24 to 85 years (mean: 60.7 years) (+13.2). Forty-five patients (51.7%) were women and 42 (48.3%) were men. The lifelong prevalence of SAD was 32.2%. However, only 16.1% presented this anxiety disorder before the beginning of PD. The prevalence of SAD with onset after PD, i.e., secondary to a movement disorder, was 16.1%, with no sex differences in SAD prevalence among PD patients.

The high rate of SAD among PD patients detected in the present study (32.1%) is comparable to those reported in other countries. However, the prevalence of patients who presented SAD before the onset of PD (16.1%) was similar to that reported for the general population. Thus, the present results suggest that the high rates of SAD among PD patients reported in the literature are due to afraid to be judged in a negative manner in public due to their tremors and other aspects of PD, rather than being related to a specific neurobiological process occurring in this movement disorder.