Antipsychotic-Related Movement Disorders: Drug-Induced Parkinsonism vs. Tardive Dyskinesia—Key Differences in Pathophysiology and Clinical Management

Changes in basal ganglia-thalamocortical motor loop due to blockade of D2 receptors by DRBAs. The blockage of D2 receptors by DRBAs in the striatum leads to disinhibition of GABA- and encephalin-containing striatal neurons at the origin of the indirect pathway, followed by a disinhibition of the subthalamic nucleus. This leads to increased GABAergic inhibition of the thalamocortical projection by facilitation of the inhibitory projection from the GPi/SNr (a). Chronic D2 receptor blockade also induces changes in the direct pathways of the basal ganglia-motor loop to cause orolingual dyskinesia (b). DA dopamine, DRBAs dopamine receptor blocking agents, GABA gamma-aminobutyric acid, GPe globus pallidus pars externa, GPi globus pallidus pars internal, SNc substantia nigra pars compacta, SNr substantia nigra pars reticulata, STN subthalamic nucleus, TD tardive dyskinesia