Which statement correctly describes the mechanism distinguishing atypical antipsychotics from typical antipsychotics?

Which statement correctly describes the mechanism distinguishing atypical antipsychotics from typical antipsychotics?

• A. They only block dopamine D2 receptors with no serotonin activity
• B. They are serotonin receptor agonists
• C. They block dopamine D2 receptors and 5-HT2A receptors
• D. They principally act on norepinephrine receptors

Answer: (C)

Atypical antipsychotics distinguish themselves by a dual action: blocking dopamine D2 receptors and blocking serotonin 5-HT2A receptors. This combination reduces positive symptoms through D2 blockade in key pathways, while 5-HT2A antagonism modulates dopamine release in other circuits, particularly increasing dopamine in the prefrontal cortex. That helps lessen extrapyramidal symptoms and can improve negative symptoms and cognitive aspects, which typical antipsychotics—primarily D2 blockers with little 5-HT2A activity—tend to cause more EPS and have less impact on negative symptoms. The other statements don’t fit because they describe either serotonin agonism, exclusive D2 action, or primary norepinephrine effects, none of which capture the defining dual D2 and 5-HT2A antagonism of atypical antipsychotics.

Atypical antipsychotics distinguish themselves by a dual action: blocking dopamine D2 receptors and blocking serotonin 5-HT2A receptors. This combination reduces positive symptoms through D2 blockade in key pathways, while 5-HT2A antagonism modulates dopamine release in other circuits, particularly increasing dopamine in the prefrontal cortex. That helps lessen extrapyramidal symptoms and can improve negative symptoms and cognitive aspects, which typical antipsychotics—primarily D2 blockers with little 5-HT2A activity—tend to cause more EPS and have less impact on negative symptoms. The other statements don’t fit because they describe either serotonin agonism, exclusive D2 action, or primary norepinephrine effects, none of which capture the defining dual D2 and 5-HT2A antagonism of atypical antipsychotics.