OCD (Obsessive Compulsive Disorder) is a condition characterised by distressing obsessive or ruminating thoughts, which in turn lead the person to perform certain actions compulsively. Common obsessions include contamination, thoughts about order or organisation and religious or sexual thoughts. Common compulsions include checking, cleaning, counting or ordering.

The presence of insight usually distinguishes OCD from psychotic illnesses, with individuals usually recognising the obsessive thoughts as their own.

It is usually a chronic disorder and is ranked by the World Health Organisation in the top ten of the most disabling illnesses by lost income and decreased quality of life.

What we already know

OCD is commonly viewed as an anxiety disorder and is strongly associated with other anxiety disorders. It also has a high level of comorbidity with depression.

Effective treatments include Cognitive Behavioural Therapy (including Exposure and Response Prevention), self-help groups, antidepressants and combined psychological and pharmacological treatments.

Areas of uncertainty

The aetiology of OCD remains unclear. Biological and psychological causal theories have been proposed, as well as genetic changes that may predispose certain individuals to the disorder.

A challenging area is the detection and treatment of OCD in children and we still know little about the links between OCD and mortality and suicide.

If the initial response to treatment with antidepressants is poor, there are augmentation strategies, including antipsychotics and other pharmacological treatments, although little is known about the definitive approach when using these.

What’s in the pipeline?

Existing medications for OCD mainly target the neurotransmitters serotonin and dopamine. However, there has been a proposed theory that symptoms result from an imbalance of the neurotransmitter glutamate, providing a new focus for future research.

Research is also ongoing into the role of electroconvulsive therapy, neurosurgery and deep brain stimulation in treating OCD.


‘Obsessive compulsive disorder’ NICE evidence update 47, Sep 2013 [PDF]

‘Obsessive-compulsive disorder: core interventions in the treatment of obsessive-compulsive disorder and body dysmorphic disorder’ NICE clinical guideline 31, 2005 [PDF]

‘Obsessive-compulsive disorder and body dysmorphic disorder’ NICE Pathway [PDF]

Common mental health disorders: Identification and pathways to care. NICE, CG123, May 2011. [PDF]

Semple, D. and Smyth, R. (eds.) (2013) Oxford Handbook of Psychiatry. 3rd ed. Oxford: Oxford University Press [Publisher]


Written by: Josephine NealePatrick Kennedy-Williams
Reviewed by:
Last updated: Sep 2015
Review due: Sep 2016

Our OCD Blogs

The economic cost of OCD in the UK: who pays?


Chris Sampson evaluates a cost-of-illness analysis on the economic burden of Obsessive Compulsive Disorder in the UK.

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Can brain scans tell us how successful CBT for anxiety will be? Meta-analysis of task-based fMRI studies shows promise


Millie Lowther, Isabel Luetkenherm, Carlos Mena and Alexandra Pike summarise a recent fMRI meta-analysis, which finds that activation in brain circuits related to salience, interoception and emotional processing were found to predict a positive response to CBT in anxiety disorders.

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Youth mental health interventions: umbrella review presents efficacy and acceptability data


In his debut blog, Nick Meader tackles a huge umbrella review of youth mental health interventions, which presents the efficacy and acceptability of 72 different approaches to help children and young people.

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Checking compulsions in OCD: responsibility, probability and severity of harm #BABCP2022


In her debut blog, Christine Purdon explores a model of checking compulsions in those with OCD, finding that severity and likelihood of harm are important. This research led by Adam Radomsky will be presented at the #BABCP2022 conference in London later this week.

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Social media peer support groups for OCD and related disorders: helpful or harmful?


In her debut blog, Margherita Zenoni explores a mixed methods survey, which finds that social media support groups may be harmful for some people with OCD or related disorders.

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Why CBT can fail those with OCD: service users’ perspectives


In his debut blog, Lawson Taylor summarises a preprint qualitative study that explores the views of service users with OCD or panic disorder, and tries to offer some answers as to why CBT does not work well for some people.

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Are antidepressants safe? A new umbrella review of observational studies suggests they are, but we need more accurate data


Andrea Cipriani and Anneka Tomlinson scrutinise a brand new umbrella review of the associations between antidepressants and adverse health outcomes, which suggests that antidepressants are safe for most people who experience mental health difficulties.

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Internalising problems in children and adolescents: little evidence for distinct disorders


Katie Finning explores a recent network analysis of internalising disorders (e.g. depression, anxiety, phobias) in children and adolescents, which demonstrates the interconnected nature of internalising symptoms, and challenges the view that such pathology takes the form of distinct disorders.

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Younger mums may be at higher risk of mental health problems #ESMI


Jennifer Burgess summarises the results of a small cross-sectional study of young pregnant women at risk of mental disorders, which found that young women had greater odds of having a common mental disorder and CMDs were associated with living alone and abuse.

Follow #ESMI today on Twitter for all of the updates from the ESMI study day (Effectiveness of Services for Mothers with Mental Illness).

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CBT for anxiety: new meta-analysis confirms significant improvements to target symptoms

CBT plus taper is effective at reducing benzodiazepine use in the short term (3 months) but this effect is not sustained at 6 months.

Inês Pote summarises a recent meta-analysis of randomised placebo-controlled trials of cognitive behavioural therapy for anxiety and related disorders.

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