2 Neuroscience2.11 Integrated neurobiology of syndromes and states
2.11.6 Obsessive compulsive and related disorders
1 min read1 figure
Written by Resident Doctor Committee · Published
The disordered circuit
The cortico-striato-thalamo-cortical loop is the circuit disordered in obsessive-compulsive disorder (OCD), rather than the Papez circuit or other limbic networks.
Evidence for this loop comes from imaging, lesion surgery and deep brain stimulation.
Loop | Cortical origin | Striatal territory |
|---|---|---|
Affective | Orbitofrontal and ventromedial prefrontal cortex | Ventral striatum, ventromedial caudate |
Associative | Dorsolateral prefrontal and anterior cingulate cortex | Dorsomedial caudate |
Sensorimotor | Sensorimotor cortex, supplementary motor area | Putamen |
Imaging
Resting positron emission tomography shows increased metabolism in the orbitofrontal-caudate loop, not reduced metabolism.
Functional imaging shows abnormal basal ganglia metabolism in the caudate and lentiform nucleus.
Raised caudate metabolism normalises with successful treatment. Both medication and exposure with response prevention can change these circuits.
Physical treatments
Selective serotonin reuptake inhibitors and clomipramine are effective, and an adequate trial often takes 10 to 12 weeks.
Cingulotomy, capsulotomy and deep brain stimulation are reserved for selected severe refractory cases.
The deep brain stimulation target for refractory OCD is the anterior limb of the internal capsule, whereas the target for depression is the subgenual cingulate cortex.
Related disorders
Disorder | Core feature | Treatment point |
|---|---|---|
Body dysmorphic disorder | Distressing preoccupation with appearance | Insight varies; assess suicide risk |
Hoarding disorder | Difficulty discarding, often with clutter | Needs adapted treatment |
Trichotillomania | Recurrent hair pulling with hair loss | Habit reversal |
Excoriation disorder | Recurrent skin picking causing lesions | Behavioural treatment of triggers and habits |