Neuroimaging of psychotherapy for obsessive–compulsive disorder: A systematic review

• OCD is associated with neural dysfunction in frontal–striatal dorsal and ventral circuits.
• Activation often normalizes along with some gray matter growth after efficacious CBT.
• Neural normalization is often associated with symptomatic and cognitive recovery.
• Pharmacotherapy and psychotherapy may have similar effects on neural functioning.

The symptoms of obsessive–compulsive disorder (OCD) include intrusive thoughts, compulsive behavior, anxiety, and cognitive inflexibility, which are associated with dysfunction in dorsal and ventral corticostriato-thalamocortical (CSTC) circuits. Psychotherapy involving exposure and response prevention has been established as an effective treatment for the affective symptoms, but the impact on the underlying neural circuits is not clear. This systematic review used the Medline, Embase, and PsychINFO databases to investigate how successful therapy may affect neural substrates of OCD. Sixteen studies measuring neural changes after therapy were included in the review. The studies indicate that dysfunctions in neural function and structure are partly reversible and state-dependent for affective symptoms, which may also apply to cognitive symptoms. This is supported by post-treatment decreases of symptoms and activity in the ventral circuits during symptom provocation, as well as mainly increased activity in dorsal circuits during cognitive processing. These effects appear to be common to both psychotherapy and medication approaches. Although neural findings were not consistent across all studies, these findings indicate that people with OCD may experience functional, symptomatic, and neural recovery after successful treatment.