Obsessive–compulsive disorder

Obsessive–compulsive disorder (OCD) is a mental disorder in which an individual has intrusive thoughts (an obsession) and feels the need to perform certain behaviors (compulsions) repeatedly to relieve the distress caused by the obsession, to the extent where it impairs general function.

Obsessions are persistent unwanted thoughts, mental images, or urges that generate feelings of anxiety, disgust, or discomfort. Some common obsessions include fear of contamination, obsession with symmetry, the fear of acting blasphemously, sexual obsessions, and the fear of possibly harming others or themselves. Compulsions are repetitive actions performed in response to obsessions to reduce anxiety, such as washing, checking, counting, reassurance seeking, and situational avoidance.

Compulsions occur often and typically take up at least one hour per day, impairing one's quality of life. Compulsions temporarily relieve distress but reinforce obsessions over time. Many adults with OCD recognize their rituals as irrational yet continue them to reduce anxiety. For this reason, thoughts and behaviors in OCD are usually considered egodystonic (inconsistent with one's ideal self-image).

The exact causes of OCD are unknown, but there is evidence for the presence of a genetic component to the disorder. A variety of social and environmental factors can also contribute to the development of OCD. Diagnosis is based on clinical presentation; rating scales such as the Yale–Brown Obsessive–Compulsive Scale (Y-BOCS) assess severity. OCD is associated with a general increase in suicidality. The term obsessive–compulsive or OCD is often used informally to describe someone overly meticulous or fixated, but OCD can present in many ways, and not all sufferers focus on cleanliness or symmetry.

OCD is chronic and long-lasting with periods of severe symptoms followed by periods of improvement. Treatment can improve ability to function and quality of life, and is usually reflected by improved Y-BOCS scores. First-line treatment for OCD typically consists of either exposure and response prevention or pharmacotherapy with selective serotonin reuptake inhibitors (SSRIs), or both in combination. Some patients fail to improve after treatment with SSRIs alone; these cases qualify as treatment-resistant and can require second-line treatment such as clomipramine or atypical antipsychotic augmentation. Recent evidence for treatment-resistant OCD also supports adjunctive use of deep brain stimulation, neurosurgical ablation, and repetitive transcranial magnetic stimulation.

OCD can present with a wide variety of symptoms. Certain groups of symptoms usually occur together as dimensions or clusters, which may reflect an underlying process. The standard assessment tool for OCD, the Yale–Brown Obsessive–Compulsive Scale (Y-BOCS), has 13 predefined categories of symptoms. These symptoms fit into three to five groupings. A meta-analytic review of symptom structures found a four-factor grouping structure to be most reliable: symmetry factor, forbidden thoughts factor, cleaning factor and hoarding factor. The symmetry factor correlates highly with obsessions related to ordering, counting and symmetry, as well as repeating compulsions. The forbidden thoughts factor correlates highly with intrusive thoughts of a violent, religious or sexual nature. The cleaning factor correlates highly with obsessions about contamination and compulsions related to cleaning. The hoarding factor only involves hoarding-related obsessions and compulsions, and was identified as being distinct from other symptom groupings.

When examining the onset of OCD, one study suggests that there are differences in the age of onset between males and females, with the average age of onset of OCD being 9.6 years for boys and 11.0 years for girls. Children with OCD often have other mental disorders, such as ADHD, depression, anxiety and disruptive behavior disorder. Continually, children are more likely to struggle in school and experience difficulties in social situations (Lack 2012). When looking at both adults and children, a study found the average ages of onset to be 21 and 24 for males and females respectively. While some studies have shown that OCD with earlier onset is associated with greater severity, other studies have not been able to validate this finding. Looking at women specifically, a different study suggested that 62% of participants found that their symptoms worsened at a premenstrual age. Across the board, all demographics and studies showed a mean age of onset of less than 25.

Some OCD subtypes have been associated with improvement in performance on certain tasks, such as pattern recognition (washing subtype) and spatial working memory (obsessive thought subtype). Subgroups have also been distinguished by neuroimaging findings and treatment response, though neuroimaging studies have not been comprehensive enough to draw conclusions. Subtype-dependent treatment response has been studied and the hoarding subtype has consistently been least responsive to treatment.