Obsessive-compulsive disorder

  • Obsessions
    • unwanted, distressing images, thoughts, doubts, impulses
    • recognised by patient as absurd or inappropriate
    • repeatedly intrude into consciousness despite patients resistance to them
    • (DSM-IV serving to raise anxiety)
  • Compulsions
    • repetitive behaviours which patient feels compelled to carry out
    • though recognised as senseless
    • may serve to reduce anxiety
    • (DSM-IV thoughts or behaviours that reduce anxiety)

Classification

ICD-10

Neurotic, stress-related and somatoform disorders

  • F42 - OCD
  • F42.0 predominantly obsessional
  • F42.1 predominantly compulsive
  • F42.2mixed
 DSM-IV

Anxiety Disorder

 (no subtypes)

Clinical Features

  • Persistent thoughts, ruminations, images, doubts or impulses
  • Content repugnant, worrying, blasphemous, obscene, nonsensical
  • Common examples of obsessions
    • dirt
    • contamination
    • sex
    • religion
    • aggression
    • orderliness
    • socially unacceptable actions
  • Common examples of compulsions
    • Cleaning (51%)
      • More common in women
    • Repeating (40%)
    • Checking (38%)
      • more common in men
    • Orderliness (9%)
    • Hoarding (2%)
  • distinguish between anxiogenic and anxiolytic thoughts

Epidemiology

  • One month prevalence 1.3%
  • Male=female
  • Onset insidious in early 20s
    • 92% are between 10 and 40 years, mean age 22, mean age at presentation 34
  • Males earlier than females
  • excess of life events in year prior to onset
  • fewer married
  • those seeking treatment are of slightly raised intelligence and social class

Associations

Differential diagnosis

Aetiology of phobias and OCD

  • Often fear provoking stimulus in OCD (CF phobia)
  • Evolutionary basis of fear of animals, strangers, dark
  • genetics - slight increased prevalence for OCD and blood phobia
  • neurochemistry
    • Noradrenaline
    • serotonin
    • GABA
  • Psychoanalytic
    • anxiety aroused by phobic object
    • OCD caused by unconscious conflicts (sexual or aggressive)
    • OCD regression to anal phase of development
  • Learning theory

Management

Prognosis

  • response to CBT ± drugs is 60% (placebo 5%)
  • significant suicide risk (esp. if coexisting depression)