Reduced striatal dopamine D2/3 receptor availability in Body Dysmorphic Disorder

Area of Science:

• Neuroscience
• Psychiatry
• Radiology

Background:

• The dopaminergic system is implicated in Obsessive Compulsive and Related Disorders (OCRD).
• Body Dysmorphic Disorder (BDD) has not been previously investigated in-vivo for dopaminergic system involvement.
• Reduced striatal dopamine D2/3 receptor availability is a consistent finding in Obsessive Compulsive Disorder (OCD).

Purpose of the Study:

• To investigate in-vivo striatal dopamine D2/3 receptor availability in patients with BDD.
• To test the hypothesis that BDD patients have lower dopamine D2/3 receptor availability than healthy subjects.
• To explore the pathophysiological basis for BDD's reclassification within the OCRD spectrum.

Main Methods:

• Single Photon Emission Computed Tomography (SPECT) using [(123)I]iodobenzamide.
• Examination of striatal dopamine D2/3 receptor Binding Potential (BPND) in 12 drug-free BDD patients and 12 matched controls.
• Regions of interest included the caudate nucleus and putamen, with BPND calculated relative to occipital cortex binding.

Main Results:

• Significantly lower dopamine D2/3 receptor BPND was observed in BDD patients compared to controls.
• This reduction was significant in both the putamen (p=0.017) and the caudate nucleus (p=0.022).
• This study provides the first in-vivo evidence of dopaminergic system disturbance in BDD.

Conclusions:

• The findings demonstrate a disturbed dopaminergic system in BDD patients.
• This provides pathophysiological support for the recent reclassification of BDD to the OCRD in DSM-5.
• The results highlight the role of the dopamine system in BDD.