OCD: What is obsessive-compulsive disorder?

OCD is a common and distressing mental illness characterised by recurrent obsessions and compulsions.

Obsessions are intrusive and unwanted images, thoughts and ideas which cause anxiety and distress.

Compulsions are thoughts or behaviours which aim to reduce the anxiety caused by the obsessional thoughts.

In reality compulsions relieve anxiety only by a little, but enough to reinforce the compulsion so it is performed repetitively. Mental rituals, such as repeating a phrase in the mind, can be more difficult to recognise and therefore for the patient to resist and treat.

Common features of OCD

Obsessions

• Fear of contamination
• Need to perform actions perfectly
• Fear of causing harm to others by acts of omission
• Fear of causing harm to self by acts of omission
• Fear of causing harm to others by acts of commission
• Fear of causing harm to self by acts of commission
• Fear of loss of objects or information
• Religious obsessions often fear of committing blasphemy
• Requirement for symmetry

Compulsions

• Decontamination, cleaning and washing
• Checking and repeating
• Magical rituals, e.g saying a rhyme or having a good number to undo the harm of the obsessive thought
• Hoarding

In addition, many patients may repeatedly seek reassurance from others as a way of reducing anxiety.

What is obsessive-compulsive disorder?

Differential diagnosis and suggested screening questions

Epidemiology and aetiology

Treatment approaches

Further resources for patients and practitioners

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