OCD: a professionals' guide

This guide provides an overview of the definition, diagnosis and treatment of obsessive-compulsive disorder, along with links to further information.

Differential diagnosis and screening questions

Differential diagnosis

  • The main differential diagnosis is depression and many patients with OCD have comorbid depressive symptoms.
  • Other differentials include phobic disorders, anorexia nervosa, obsessive or anakastic personality and occasionally schizophrenia.
  • The symptoms of OCD are seen in other conditions such as Tourette's syndrome, autism and frontal lobe lesions.
  • Obsessive-compulsive-related disorders (OCRD) and a range of disorders which share characteristics with OCD (e.g. in symptom profile, biology and treatment outcome).
  • OCRDs include body dysmorphic disorder (BDD - concerns of imagined ugliness), hypochondriasis (concerns about imagined illness), eating disorders and impulse control disorders such as trichotillomania (hair pulling).

 Screening questions for OCD*

  1. Do you have frequent unwanted thoughts that seem uncontrollable?
  2. Do you try to get rid of these thoughts and, if so, what do you do?
  3. Do you have rituals or repetitive behaviours that take a lot of time in a day?
  4. Do you wash or clean a lot?
  5. Do you keep checking things over and over again?
  6. Are you concerned with symmetry and putting things in order?
  7. Do your daily activities take a long time to complete?
  8. Do these problems trouble you?
  9. Does this behaviour make sense to you?

Non-psychiatrists who may be referred patients with OCD

Who can refer
Reason for consultation
GP Anxiety, depression
Dermatologist Chapped hands, eczema, trichotillomania
Cosmetic surgeon Concerns about appearance
Oncologist Fear of cancer
Genitourinary specialist Fear of HIV
Neurologist OCD associated with Tourette's syndrome
Obstetrician OCD in pregnancy
Gynaecologist Vaginal discomfort from douching

*These screening questions were compiled from the following articles:

  • El-Sayegh S, Bea S and Agelopoulos A. "Obsessive Compulsive Disorder: Unearthing a hidden problem". Cleveland Clinic Journal of Medicine (2003) 70, Number 10: 824-840
  • National Collaborating Centre for Mental Health commissioned by the National Institute for Health and Clinical Excellence. "Obsessive-compulsive disorder: Core interventions in the treatment of obsessive-compulsive disorder and body dysmorphic disorder". National Clinical Practice Guideline, Number 31. Published by The British Psychological Society and The Royal College of Psychiatrists, Jan 2006
  • Heyman I, Mataix-Cols D, Fineburg N A. "Obsessive-compulsive disorder". BMJ (2006), 333: 424-429

Epidemiology and aetiology


  • OCD is observed in males and females in approximately equal proportions.
  • Prevalence may be as high as 1% to 3% in adults and 1% to 2% in childhood/ adolescence (especially just before the onset of puberty).
  • Many adult sufferers report symptoms appearing for the first time in childhood or adolescence.
  • Men more frequently present with checking rituals and women are more likely to display compulsive washing. 
  • The course of OCD is usually chronic but may vary in severity in response to stress. 
  • Many individuals do not present to healthcare professionals until early in middle age. 


  • Multifactorial in origin.
  • Includes environmental and hereditary factors.
  • Brain imaging studies have identified the basal ganglia and orbitofrontal cortex to be involved in the development of OCD.

Treatment approaches

The 2005 NICE guidelines for the treatment of OCD and body dysmorphic disorder (BDD) encourage the use of a stepped-care model. The model aims to provide OCD sufferers with the least intrusive but most effective management for the patients needs. Each step provides successively greater intervention, assuming the previous step has already been implemented but has been unsuccessful. The model tailors the level of intervention to characteristics of the sufferers OCD and emphasizes the benefits of involving the family, schools and social workers.

stepped care model for ocd


















Psychological therapy

Exposure Response Prevention (ERP) is a form of cognitive behaviour therapy (CBT) and produces response rates of 85% in subjects who complete therapy. Patients are first required to produce a hierarchy of anxiety-inducing situations. The client then faces the feared situations or objects without performing the compulsive ritual. The objective of ERP is to produce habituation, where anxiety reduces naturally after prolonged exposure to the stimulus. A reduction in anxiety is seen within 60-90 minutes if the patient does not engage in anxiolytic behaviours. The patient works through the graded hierarchy tackling the least feared challenges first.  

ERP can be delivered in a variety of forms, including self-help programs such as books, computer packages and telephone therapy. These provide a self-directed approach to overcoming OCD but with some therapist input for goal identification and early education. CBT often has long waiting lists and is demanding on therapists time. Self-help approaches have the potential to help more patients with minimal input from a clinician and may be monitored at the primary care level.

Psychological interventions for children with OCD follow similar principles as adult-based therapies. It is important to acknowledge developmental discrepancies and language ability in children. Significant emphasis should also be placed on involvement of the family. 

Find out about the National OCD/BDD service provided by the Trust.