title: Obsessive-compulsive disorder: a disorder of pessimal (non-functional) motor behavior.
abstract: OBJECTIVE
  To determine whether in addition to repetitiveness, the motor rituals of patients with obsessive-compulsive disorder (OCD) involve reduced functionality due to numerous and measurable acts that are irrelevant and unnecessary for task completion.
  
  
  METHODS
  Comparing motor rituals of OCD patients with behavior of non-patient control individuals who were instructed to perform the same motor task.
  
  
  RESULTS
  Obsessive-compulsive disorder behavior comprises abundant acts that were not performed by the controls. These acts seem unnecessary or even irrelevant for the task that the patients were performing, and therefore are termed 'non-functional'. Non-functional acts comprise some 60% of OCD motor behavior. Moreover, OCD behavior consists of short chains of functional acts bounded by long chains of non-functional acts.
  
  
  CONCLUSIONS
  The abundance of irrelevant or unnecessary acts in OCD motor rituals represents reduced functionality in terms of task completion, typifying OCD rituals as pessimal behavior (antonym of optimal behavior).
authors.affiliation: Department of Zoology, Tel-Aviv University, Ramat-Aviv, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Zor
authors.forename: H
authors.initials: H
authors.lastname: Keren
authors.forename: H
authors.initials: H
authors.lastname: Hermesh
authors.forename: H
authors.initials: H
authors.lastname: Szechtman
authors.forename: J
authors.initials: J
authors.lastname: Mort
authors.forename: D
authors.initials: D
authors.lastname: Eilam
mesh_terms: D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D015995:Prevalence; D011596:Psychomotor Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D012720:Severity of Illness Index; D019956:Stereotypic Movement Disorder / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D014743:Videotape Recording; D055815:Young Adult