Antipsychotic drugs primarily achieve their effect by which mechanism?

• A. block dopamine receptors
• B. block acetylcholine receptors
• C. increase serotonin release
• D. block GABA receptors

Answer: (A)

Antipsychotics work mainly by blocking dopamine D2 receptors in brain circuits that mediate thought and perception. By occupying these receptors, they dampen dopamine signaling in the mesolimbic pathway, which helps lessen positive psychotic symptoms like delusions and hallucinations. The other listed mechanisms don’t drive the therapeutic effect: blocking acetylcholine receptors leads to anticholinergic side effects rather than symptom relief; increasing serotonin release isn’t how these drugs primarily work (though some atypical antipsychotics affect serotonin as well); and blocking GABA receptors wouldn’t produce the antipsychotic benefit and could worsen symptoms. So, the primary action is dopamine receptor blockade.