Cervical dystonia and substance abuse

Objective: To investigate the prevalence of substance abuse (SA) in patients with cervical dystonia (CD) and to correlate it with prevalence of psychiatric disorders.

Methods: Data on anxiety, depression, dystonia severity, and substance abuse were collected from ten sites participating in the Dystonia Coalition. Patients were divided into two groups according to the presence of SA, utilizing Structured Clinical Interview for DSM-4 criteria. Wilcoxon Rank-Sum test was used to analyze the difference in median scores on the questionnaires between the groups. Chi-square test was used to analyze association between opiate and benzodiazepine use and SA. Association between TWSTRS severity and SA and medication use was assessed. A two-tailed p value of < 0.05 was considered significant. SAS 9.3 (SAS Institute Inc., Cary, NC, USA) was used for all analyses.

Results: Of 208 CD patients, 23 (11%) were identified with SA; 26.3% of patients with SA were on opiates compared to 7.2% of CD patients without SA (p = 0.006). Compared to non-SA patients, those experiencing SA were more likely male (88.9%; p = 0.0007), younger (median age 55; p = 0.031), and scored worse on questionnaires assessing depression (p = 0.044, p = 0.005), anxiety (p = 0.003), and dystonia psychiatric severity (p = 0.033). The median TWSTRS motor severity scores were higher in SA patients compared to non-SA patients (20 versus 16, p = 0.0339). The median TWSTRS total disability, motor, and pain scores were higher in patients on opiates than patients who were not (12 versus 8, p = 0.0071; 18.5 versus 16, p = 0.0243; 12.4 versus 6.7, p = 0.0052, respectively).

Conclusions: Potential risk factors for SA in CD patients include younger age and male gender with comorbid anxiety, depression and other psychiatric problems. Caution should be exercised when prescribing drugs with potential for abuse in these patients.