Primary focal dystonia (PFD) is an idiopathic movement disorder that manifests as involuntary, sustained muscle contractions, leading to abnormal postures. Its pathophysiology probably involves a functional disorder of the basal ganglia and their frontal cortical connections. The hypothetical association with obsessive-compulsive disorder (OCD) has raised particular interest, as both disorders seem to involve frontal cortical-basal dysfunction. Anyway, evidence supporting this association is scarce and contradictory.

To address the next two questions: (1) Do primary dystonia patients have high obsessive-compulsive symptom scores? (2) Are these symptoms more severe in dystonia than in controls with equivalent peripheral neurological disorders?

We’ve conducted a cross-sectional, descriptive, controlled study comprising 45 consecutive patients with PFD (i.e., blepharospasm, spasmodic torticollis, or writer's cramp), 46 consecutive patients with hemifacial spasm, cervical spondylarthropathy, or carpal tunnel syndrome, and 30 healthy volunteers. Assessment included the DSM-IV based psychiatric interview, Symptom Check- list 90R, Yale-Brown Obsessive-Compulsive Scale and Checklist, and the Unified Dystonia Rating Scale.

Dystonia patients had higher Yale-Brown scores than both control groups. Major depression and generalized anxiety disorder were the most frequent psychiatric diagnoses in PFD. Obsessive-compulsive disorder frequency was 6.7%. PFD patients have higher obsessive-compulsive symptom scores than individuals with similar functional disabilities resulting from other neurological disorders, suggesting that obsessive-compulsive symptoms in dystonia are not reactive to chronic disability.

Dystonic muscle contractions and obsessive-compulsive symptoms may share a common neurobiological basis related to cortical-basal dysfunction. Psychopathology, especially obsessive-compulsive symptoms, should be actively explored and treated in primary focal dystonia.