<prompt> Irresistable urge to do a thing repeatedly is seen inObsessive compulsive disorderSchizophreniaSchizoaffective disorderDepression  <response>: Ans. a Obsessive compulsive disorder. Ref Harrison, Medicine, 18thch. 391OBSESSIVE-COMPULSIVE DISORDER OCD Definition- is a psychiatric disorder, specifically, an anxiety disorder. OCD is manifested in a variety of forms, but is most commonly characterized by a subjects obsessive repetitive, distressing, intrusive thoughts and related compulsions tasks or rituals which attempt to neutralize the obsessions.- Characterized by recurrent Obsessions or Compulsions that are recognized by the individual as unreasonable- Undoing Compulsion Acts in Obsessive Compulsive Disorder.- Obsessions: Anxiety-Provoking Intrusive Thoughts commonly concerning Contamination, Doubt, Guilt, Aggression Sex- Compulsions: Peculiar Behaviors that reduce Anxiety via Hand-Washing, Organizing, Checking, Counting Praying Risk FactorsEtiology- Associated with abnormalities of Serotonin metabolism Prevalence:- 2 of population.- Occurs at a 1 to 1 male-to-female ratio Onset:- Insidious occurs during childhood, adolescence or early adulthood Physical Examination- Chapped hands when hand-washing compulsion is present Treatment- Pharmacotherapy: SSRI Fluoxetine or Fluvoxamine Clomipramine- Behavioral Psychotherapies: Relaxation Training, Guided Imagery, Exposure,- Response Prevention, Thought Stopping Techniques Modeling 