Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is characterized by recurrent, intrusive, and unwanted thoughts, images, or urges (obsessions) that provoke marked anxiety, and by repetitive behaviors or mental acts (compulsions) that the person feels driven to perform to reduce the distress or prevent a feared outcome. In children and adolescents, common themes include contamination, harm, symmetry, and forbidden thoughts, with corresponding washing, checking, ordering, and reassurance-seeking. Current diagnostic systems classify OCD outside the anxiety disorders, in an obsessive-compulsive and related disorders grouping.

Definition

A disorder defined by the presence of obsessions (recurrent and persistent intrusive thoughts, urges, or images experienced as unwanted and distressing) and/or compulsions (repetitive behaviors or mental acts performed in response to an obsession or rigid rules), which are time-consuming or cause clinically significant distress or impairment.

Scope

This entry covers the clinical concept of obsessions and compulsions, neurobiological and genetic features, epidemiology and onset, and the evidence base for treatment in youth. It is educational reference material and does not provide diagnostic thresholds or treatment instructions for individuals.

Core questions

• How do obsessions and compulsions relate to and reinforce one another?
• What distinguishes OCD from the anxiety disorders?
• What is known about the neurobiology and genetics of OCD?
• What treatments are best supported in children and adolescents?

Key concepts

• Obsessions and compulsions
• Anxiety reduction as negative reinforcement of compulsions
• Cortico-striato-thalamo-cortical circuit involvement
• Substantial heritability
• Childhood and adolescent onset in many cases
• Exposure and response prevention as core psychotherapy

Mechanisms

OCD is understood through a learning model in which compulsions transiently relieve the anxiety provoked by obsessions, thereby negatively reinforcing and perpetuating the cycle; this rationale underlies exposure and response prevention. Neurobiologically, OCD is associated with dysfunction in cortico-striato-thalamo-cortical circuits, and it has a substantial genetic component, with integrative accounts linking genetic, neuroimaging, and neuropsychological findings. Pediatric OCD often differs from adult-onset OCD in features such as male predominance and higher rates of comorbid tic disorders.

Clinical relevance

OCD can be highly time-consuming and impairing in young people, affecting school, family life, and development, and it frequently co-occurs with other anxiety disorders, tic disorders, and depression. This entry summarizes how the condition is conceptualized and studied for reference; it is not a basis for self-diagnosis or individualized care.

Epidemiology

OCD is less common than the anxiety disorders but frequently begins in childhood or adolescence, with a notable proportion of lifetime cases having early onset. Pediatric OCD shows a relative male predominance and elevated rates of comorbid tic disorders compared with adult-onset presentations, and it tends to be chronic without treatment.

Evidence & guidelines

The AACAP practice parameter for pediatric OCD (Geller & March, 2012) addresses assessment and treatment, and the Pediatric OCD Treatment Study (POTS Team, 2004) is a landmark randomized trial showing benefit of cognitive behavioral therapy, sertraline, and especially their combination. These are summarized for reference and are not treatment direction.

History

OCD was historically grouped with the anxiety disorders, but accumulating neurobiological and phenomenological evidence led DSM-5 and ICD-11 to place it in a distinct obsessive-compulsive and related disorders category. Research clarified the role of cortico-striato-thalamo-cortical circuitry and heritability, and the POTS trial in 2004 established the efficacy of exposure-based cognitive behavioral therapy and serotonergic medication in young people.

Debates

Should OCD be classified with the anxiety disorders?

Although OCD shares anxiety-related features and historically sat among the anxiety disorders, distinct neurobiology, genetics, and phenomenology led current systems to classify it separately in an obsessive-compulsive and related disorders grouping, a reclassification that remains a point of discussion in relation to its close links with anxiety.

Seminal works

• geller-2012
• pots-2004
• pauls-2014

Frequently asked questions

What is the difference between an obsession and a compulsion?

An obsession is a recurrent, intrusive, unwanted thought, image, or urge that causes distress, while a compulsion is a repetitive behavior or mental act performed to reduce that distress or prevent a feared outcome.

Is obsessive-compulsive disorder still an anxiety disorder?

Current diagnostic systems (DSM-5 and ICD-11) classify OCD separately from the anxiety disorders, in an obsessive-compulsive and related disorders grouping, although it retains close clinical and developmental links to anxiety.