title: Tic-Related Versus Tic-Free Obsessive-Compulsive Disorder: Clinical Picture and 2-Year Natural Course.
abstract: OBJECTIVE
  The tic-related subtype of obsessive-compulsive disorder (OCD) has a distinct clinical profile. The course of tic-related OCD has previously been investigated in treatment studies, with inconclusive results. This study aimed to compare clinical profiles between tic-related and tic-free OCD patients and to establish the influence of tics on the 2-year natural course in adult OCD patients.
  
  
  METHODS
  Within the Netherlands OCD Association cohort, 377 patients with a current DSM-IV diagnosis of OCD were divided into a tic-related group (28%) and a tic-free group and compared on clinical variables with t tests or χ² tests. Linear mixed-model analyses were used to compare the 2-year course between the groups, with the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) as primary outcome measure. Data were collected from 2005 to 2007 and from 2007 to 2009.
  
  
  RESULTS
  Compared to patients with tic-free OCD, those with tic-related OCD reported earlier disease onset (P = .009) and more symmetry/ordering symptoms (P = .002). Overall symptom severity was similar in both groups. Patients with tic-related OCD reported increased traits of attention-deficit hyperactivity (P < .001) and autism (P = .005) compared to the tic-free OCD group. Clinical improvement at 2-year follow-up (mean = 5.3-point decrease on the Y-BOCS, P < .001, 95% CI = 4.3 to 6.3) was not significantly moderated by tic status (P = .24). This remained unchanged after correcting for baseline differences.
  
  
  CONCLUSIONS
  Tics do not critically affect the 2-year course of adult OCD, but tic-related OCD shows differences from tic-free OCD, such as early onset and increased autism and ADHD traits, that may indicate a neurodevelopmental subtype.
authors.affiliation: VU University Medical Center, VUmc 02 Building, Department of Anatomy and Neurosciences, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands. fe.devries@vumc.nl, f.d.vries@nki.nl.|Department of Psychiatry, VU University Medical Center, and GGZ inGeest, Amsterdam, the Netherlands.|Department of Anatomy and Neuroscience, VU University Medical Center, Amsterdam, the Netherlands.
authors.forename: Froukje E
authors.initials: FE
authors.lastname: de Vries
authors.affiliation: Altrecht Academic Anxiety Center, Utrecht, the Netherlands.|Department of Clinical and Health Psychology, Utrecht University, the Netherlands.
authors.forename: Danielle C
authors.initials: DC
authors.lastname: Cath
authors.affiliation: Department of Psychiatry, VU University Medical Center, and GGZ inGeest, Amsterdam, the Netherlands.
authors.forename: Adriaan W
authors.initials: AW
authors.lastname: Hoogendoorn
authors.affiliation: Department of Psychiatry, VU University Medical Center, and GGZ inGeest, Amsterdam, the Netherlands.
authors.forename: Patricia
authors.initials: P
authors.lastname: van Oppen
authors.affiliation: Dimence Mental Health Care, Almelo, the Netherlands.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Glas
authors.affiliation: Department of Psychiatry, VU University Medical Center, and GGZ inGeest, Amsterdam, the Netherlands.
authors.forename: Dick J
authors.initials: DJ
authors.lastname: Veltman
authors.affiliation: Department of Psychiatry, VU University Medical Center, and GGZ inGeest, Amsterdam, the Netherlands.|Department of Anatomy and Neuroscience, VU University Medical Center, Amsterdam, the Netherlands.
authors.forename: Odile A
authors.initials: OA
authors.lastname: van den Heuvel
authors.affiliation: Department of Psychiatry, VU University Medical Center, and GGZ inGeest, Amsterdam, the Netherlands.
authors.forename: Anton J L M
authors.initials: AJ
authors.lastname: van Balkom
mesh_terms: D000328:Adult; D017668:Age of Onset; D000818:Animals; D001289:Attention Deficit Disorder with Hyperactivity / Q000145:classification / Q000175:diagnosis / Q000523:psychology; D015331:Cohort Studies; D015897:Comorbidity; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D001523:Mental Disorders / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D008875:Middle Aged; D009426:Netherlands; D009771:Obsessive-Compulsive Disorder / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology*; D010043:Outcome and Process Assessment, Health Care; D011446:Prospective Studies; D011817:Rabbits; D013981:Tic Disorders / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology*