Neurobiological correlates of obsessive-compulsive disorder (OCD): A narrative review

Obsessive-compulsive disorder (OCD) is a common and disabling, as well as underdiagnosed, neuropsychiatric condition characterized by involuntary and unwanted obsessions and/or compulsions, often accompanied by states of severe anxiety, distress and shame, as well as other comorbid disorders. Despite the extensive literature available to date, only some of the neurobiological mechanisms underlying the symptomatic manifestations of the disorder have been clarified, underlining the need for further research. The brain structures involved are hippocampus, amygdala, striatum, thalamus, dorsolateral prefrontal cortex, anterior cingulate cortex, and orbitofrontal cortex; furthermore, most studies have mainly focused on the expressive modalities and on the individual structural and functional alterations of the brain, generating sometimes conflicting data. The aim of this article is therefore to summarize and bring together the main evidence collected so far on what would appear to be the neuroanatomical correlates and mechanisms underlying the disorder and its manifestations, to provide a sufficiently clear and complete overview.