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Obsessive-compulsive disorder (OCD)
· Condition or disorder
Well replicatedStrong, repeated evidence.
A condition of intrusive, unwanted thoughts (obsessions) and repetitive rituals (compulsions) performed to ease the distress they cause.
See it on the Psychology map →What it says
Common obsessions involve contamination, fear of causing harm, and nagging doubt; compulsions include washing, checking locks, counting or mental reviewing. Rituals bring brief relief, which teaches the brain to repeat them; some patients lose hours a day. About 2 to 3 percent of people have OCD, often starting in childhood or early adulthood. DSM-5 moved it out of the anxiety disorders into its own chapter with hoarding and body dysmorphic disorder. Being neat or particular is not OCD.
Why it matters
It can be severely disabling but is very treatable: exposure and response prevention, a form of CBT, and SSRI medication help a majority of patients substantially.
The evidence
Brain imaging implicates loops linking the frontal cortex and deeper basal ganglia; twin studies show moderate heritability; controlled trials support exposure therapy and SSRIs; deep brain stimulation helps some severe cases.
Open questions
Why particular themes take hold, and whether brain-circuit differences cause OCD or result from it, remain open questions.
Connections (2)
▸Obsessive-compulsive disorder (OCD) is closely related to Anxiety disordersWell replicated
The connection
OCD's obsessions create intense anxiety and compulsions briefly relieve it, so OCD was classed as an anxiety disorder until 2013. DSM-5 gave it its own chapter because of its distinct brain circuits, repetitive behavior and links to conditions like hoarding, yet both respond to exposure therapy and SSRIs.
Who showed it and when
Classed with anxiety disorders in DSM-III (1980) and DSM-IV (1994); moved to the 'obsessive-compulsive and related disorders' chapter in DSM-5 (2013).
The evidence
Family, imaging and treatment studies show overlap with anxiety disorders but also differences, such as the central role of frontal–basal ganglia circuits.
Open questions
Whether OCD is better grouped with anxiety, with tic disorders, or with other repetitive behaviors remains debated.
▸Exposure therapy is the core treatment for Obsessive-compulsive disorder (OCD)Well replicated
The connection
In exposure and response prevention (ERP), a person with contamination fears might touch a doorknob and then resist washing. Rituals bring relief that reinforces them; blocking the ritual lets anxiety rise and then fall on its own. Repeated practice weakens both the obsession and the urge to perform compulsions.
Who showed it and when
British psychologist Victor Meyer described it in 1966 at Middlesex Hospital, London; Edna Foa and others refined and tested it from the 1970s.
The evidence
Many controlled trials show ERP substantially helps most patients who complete it; a 2005 trial led by Foa found it outperformed the drug clomipramine alone.
Open questions
Many patients keep some symptoms, some decline it as too frightening, and why some respond fully while others barely respond is unclear.