A patient on long-term haloperidol develops rhythmic, involuntary tongue movements and lip-smacking that persist even after the drug is stopped. The pathophysiology of this movement disorder involves:

• A Supersensitivity of striatal D2 receptors following chronic blockade ✓
• B Depletion of dopamine stores in the nigrostriatal pathway
• C Cholinergic excess in the caudate nucleus
• D Iron deposition in the globus pallidus

Explanation

Tardive dyskinesia (TD) results from chronic D2 receptor blockade leading to upregulation and supersensitivity of postsynaptic striatal dopamine receptors, so that even normal dopamine levels cause abnormal, excessive receptor stimulation manifesting as orofacial dyskinesias. Unlike acute EPS, TD persists or worsens after drug withdrawal. Valbenazine and deutetrabenazine (VMAT2 inhibitors) are FDA-approved treatments.

Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.