Deep brain stimulation induces striatal dopamine release in obsessive-compulsive disorder

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Obsessive-compulsive disorder (OCD) is a chronic condition linked to impaired dopaminergic neurotransmission.
• Deep brain stimulation (DBS) targeting the nucleus accumbens (NAc) shows promise for treatment-resistant OCD.
• The impact of NAc DBS on dopaminergic transmission in OCD remains unclear.

Purpose of the Study:

• To investigate the effects of NAc DBS on dopamine D2/3 receptor availability in the striatum of OCD patients.
• To correlate changes in dopamine receptor availability with plasma homovanillic acid (HVA) levels and clinical symptom severity.

Main Methods:

• Utilized [(123)I]iodobenzamide ([(123)I]IBZM) single-photon emission computed tomography (SPECT) to assess dopamine D2/3 receptor availability.
• Measured changes in [(123)I]IBZM binding potential (BP) in the striatum before and during NAc DBS.
• Correlated SPECT findings with plasma HVA levels and OCD symptom scores.

Main Results:

• Both acute (1-hour) and chronic (1-year) NAc DBS reduced striatal [(123)I]IBZM binding potential (BP) in the putamen.
• DBS-induced BP decreases were evident after 1 hour of stimulation.
• Chronic stimulation correlated with elevated plasma HVA, indicating DBS-induced dopamine release.
• Reduced BP near electrodes significantly correlated with a 45% decrease in clinical OCD symptoms.

Conclusions:

• NAc DBS stimulates striatal dopamine release in OCD patients.
• This dopamine release is linked to increased plasma HVA and significant clinical symptom improvement.
• NAc DBS may offer a therapeutic strategy by compensating for a deficient dopaminergic system in OCD.