Obsessive-compulsive Symptoms in Primary Dystonia: Reactive and Psychogenic or Primary and Neurophysiological?

Abstract

Introduction:

Primary dystonia (PDy) is an idiopathic neurological disorder causing involuntary muscle contraction. Its pathophysiology is believed to involve basal-ganglia (BG) dysfunction. A possible association with Obsessive-compulsive symptoms (OCS) is regarded as further evidence of BG involvement but remains controversial due to contradictory research data. We proposed to answer three questions:

1. 1. Do PDy patients have high OCS scores?

2. 2. Are OCS in PDy reactive?

3. 3. Does botulinum toxin treatment (BT) influence PDy psycopathology?

Subjects:

45 patients with blepharospasm, spasmodic torticollis, writer's cramp; 43 patients with hemifacial spasm, cervical spondilarthropathy, peripheral hand neuropathy; 27 healthy volunteers.

Assessment: non-structured DSM-IV based psychiatric interview; Symptom Checklist 90 Revised (SCL-90R); Yale-Brown Obsessive-Compulsive Scale (YBOCS); Unified Dystonia Rating Scale (UDRS).

Results:

PDy patients scored significantly higher than controls and healthy controls on the YBOCS (11.1 ± 7.24; 5.98 ± 4.33; 2.07 ± 0.92, both p< 0.001). Controls’ mean score was also significantly higher than healthy subjects’. Controls scored higher than PDy and healthy subjects on the SCL-90R somatization scale. BT treated PDy patients had significantly lower anxiety and somatization but higher UDRS and similar YBOCS ratings compared to untreated patients.

Discussion:

Higher ratings of OCS but not of depression, anxiety or somatization in PDy patients suggests a neurophysiological origin for OCS in PDy. However, diseased controls also scored higher than healthy subjects, suggesting that OCS may nevertheless be partly reactive in PDy. BT may decrease anxiety/depressive symptoms but not OCS, lending further strength to a possible neurophysiological aetiology for OCS in PDy.