Characteristics of Social Phobia Among Persons With Essential Tremor

Background: Social phobia symptoms have beenreported to be common among patients with essential tremor, butcharacteristics of this comorbidity have not been systematicallydescribed.

Method: Cases with essential tremor (N = 94) andcontrols without essential tremor (N = 85), ascertained frommovement disorder clinic and community samples, were evaluatedfor social phobia symptoms (using the social phobia module of theStructured Clinical Interview for DSM-IV Axis I Disorders and theLiebowitz Social Anxiety Scale), characteristics of tremor, andassociated disability (via videotaped examination, performancetest, and disability questionnaire).

Results: Lifetime combined prevalence of primarysocial phobia and clinically significant social phobia symptomsoccurring secondary to essential tremor was 32.7% (16/49) amongessential tremor patients in the clinic sample. Essential tremorcases with secondary social phobia symptoms reported a markedlylater age at onset of clinically significant social phobiasymptoms than essential tremor cases with primary social phobia(51.0 vs. 8.8 years). Cases with secondary social phobia alsoreported greater fear and avoidance of eating, drinking, andwriting in public than essential tremor cases with primary socialphobia and control subjects with social phobia. Essential tremorcases with secondary social phobia symptoms also demonstratedmore severe tremor and tremor-related disability than essentialtremor cases with primary social phobia and essential tremorcases without social phobia. Among all essential tremor cases,severity of social phobia symptoms and tremor independentlycontributed to disability.

Conclusion: Social phobia appears to occur in asubstantial minority of essential tremor patients, and severityof social phobia symptoms is associated with disability,independent of tremor severity. Persons with social phobiasymptoms secondary to essential tremor evidence clinicalcharacteristics that differ from those of persons with primarysocial phobia. Further research is needed to determine theefficacy of treatment of social phobia in essential tremorpatients with significant social phobia symptoms.