Obsessive-Compulsive Disorder (OCD)

OCD is the anxiety disorder which can have the most severe and damaging consequences on a persons life. OCD is terribly destructive to people’s lives because OCD confuses and frustrates not only the people with it but their families and loved ones as well. If untreated, it usually lasts a lifetime. Even with treatment, symptoms can often recur.

It is not all bad news though because there are effective treatments for obsessive compulsive disorder.

The disorder is characterised by obsessions or compulsions that cause marked distress, are time consuming (take more than 1 hour per day) or significantly interfere with the persons normal routine, occupational (or academic) functioning, or usual social activities or relationships. -from DSM-IV 1994.


These are defined according to the DSM IV as: “recurrent and persistent thoughts, impulses, or images that are experienced, at some time during the disturbance, as intrusive and inappropriate and that cause marked anxiety or distress”.

To explain further: obsessions are unwanted, repetitive and disturbing, thoughts, images, or impulses, that pop into the mind. For example, an urge to swear or yell at one’s boss, or while holding baby having a sudden urge to drop it.

People with OCD, thankfully, don’t carry out these kinds of thoughts, but the obsessions bedevil and stay with those who have them.

Most people who have OCD know that their obsessions are not truly real but are unable to stop them occurring or believing them.


These are defined according to the DSM IV as “repetitive behaviours (e.g. hand washing, ordering , checking) or mental acts (e.g. praying, counting, saying words silently) that the person feels driven to perform in response to an obsession, or according to rules that must be applied rigidly”.

Compulsions are repetitive mental strategies or actions which are executed to briefly reduce distress or anxiety. Sometimes, an obsessive thought can result in the anxiety; at other times, the anxiety relates to some situation or feared event that triggers the compulsion.

To give a common example, a person may wash their hands hundreds of times a day to reduce their anxiety about bacteria or germs. Or someone may have an elaborate ritual which they follow before they can leave the house. This may include getting dressed in a particular way, laying the table for breakfast with the cutlery in precise positions, then eating their breakfast foods in a certain order, brushing their teeth in a ritualised way, and then checking all the windows and doors several times before leaving.

In severe cases the rituals can be so complex and demanding that people take several hours to leave the house.

The behaviours or mental acts are designed to prevent or reduce discomfort and the likelihood of the dreaded event occurring, but the compulsions are either unrealistic or clearly excessive.

Most people with OCD realise that their behaviour is excessive or unreasonable.

It has been found that the intrusive thoughts, images, and impulses and compulsive activities that are the hallmarks of OCD are also present to a lesser degree in nearly 90% of the general population. That is, ordinary people commonly experience intrusive ideas or engage in neutralising actions as part of their everyday experience. However most do not go on to develop OCD.

Examples of obsessive and intrusive thoughts reported to psychologists by OCD sufferers:

  • Image of objects flying into my eye
  • Image of being in a car accident trapped under water
  • Idea that dirt is always on my hand
  • Impulse to say something hurtful
  • Thought of blurting something out in church
  • Thought that I haven’t locked the house up properly 
  • Thought of being fired because I am not perfect
  • Idea that objects are not arranged properly 

Some facts about OCD 

The age of onset of OCD is usually from adolescence to early 20's.

Studies have shown that there is evidence of hyperactivity in the orbito-frontal lobes in patients with OCD. With treatment this over-activity has been shown to return to normal.

Lifetime prevalence is about 1 in 45 persons.

There is a strong association between OCD and anxiety or mood disorders.

There is also a weaker association between PTSD and OCD.

Nowhere is the relationship of anxiety and depression stronger than for OCD.

Up to 80% of patients with OCD may be depressed.

Assessment tools for obsessive compulsive disorder

The assessment tools that are used by psychologists include:

  • Interviewing patients
  • Using questionnaires
  • Self-reporting by suspected sufferers, and behavioural instruments (e.g. direct observation and counting of rituals) 

A standard measure of OCD symptoms is Yale-Brown Obsessive Compulsive Scale (Y-BOCS). This is scored out of 40. The clinical cut off for OCD is 16. Y-BOCS is the standard tool for assessing severity of OCD in pharmacological and CBT trials.

With regard to interview tools, the Anxiety Disorders Interview Schedule for DSM-IV: Lifetime version (ADIS-IV-L; Di Nardo, Brown & Barlow) is the most useful for clinical purposes. A questionnaire known as the MOCI (Hodgson & Rachman 1977) has been used most frequently in research trials. This is a 30 item questionnaire. Self-monitoring scales have also been used in studies of behavioural treatments.

Case example

"I worry about germs and contamination so much that I wash my hands about 30 times a day — my hands are raw and bleeding. I just can’t stop."

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