Effect of comorbid tics on a clinically meaningful response to 8-week open-label trial of fluoxetine in obsessive compulsive disorder

Currently, there are limited published data evaluating the effects of tics on serotonin reuptake inhibitor (SRI) monotherapy responses in treating obsessive-compulsive disorder (OCD). One retrospective case-controlled analysis of OCD patients treated with SRI monotherapy showed lesser improvement in OCD symptoms in patients with tics than those without. However, more recently there were preliminary reports of OCD subjects treated with SRI monotherapy which did not demonstrate poorer response in subjects with tics or Tourette's Syndrome (TS). The specific aim of this study was to investigate whether the presence of comorbid chronic tics affected "clinically meaningful improvement" [McDougle, C.J., Goodman, W.K., Leckman, J.F., Barr, L.C., Heninger, G.R., Price, L.H., 1993. The efficacy of fluvoxamine in obsessive-compulsive disorder: effects of comorbid chronic tic disorder. Journal of Clinical Psychopharmacology 13, 354-358] of OCD in an 8-week open-label trial of fluoxetine monotherapy. Seventy-four adult subjects (13 patients with comorbid chronic tics and 61 patients without tics) with a primary DSM-IV OCD diagnosis were treated with up to 40mg fluoxetine for 8 weeks and had at least one post-baseline evaluation. The results indicate that there was a significant response by time in both fluoxetine-with-tic subjects and fluoxetine-without-tic subjects. Additionally, there were 3 (23.0%) OCD subjects with tics who had clinically meaningful improvement versus 16 (26.2%) OCD subjects without tics that demonstrated similar levels of improvement. These findings indicate that OCD patients with or without chronic tic disorders did not have a differential response to an 8-week open-label trial of fluoxetine. Limitations include the relatively low number of tic subjects and the open-label nature of the study. Additional data are needed on how comorbid tics may affect SRI treatment response in OCD.