Which of the following is an atypical antipsychotic mentioned in the material?

• A. Haloperidol
• B. Aripiprazole
• C. Chlorpromazine
• D. Risperidone

Answer: (B)

Aripiprazole is an atypical antipsychotic because it belongs to the second-generation drugs that combine dopamine receptor modulation with actions on serotonin receptors. Its standout feature is that it acts as a partial agonist at dopamine D2 receptors, meaning it can dial dopamine activity up or down rather than completely blocking it. It also has activity at serotonin receptors, including partial agonism at 5-HT1A and antagonism at 5-HT2A receptors. This combination helps reduce positive symptoms while minimizing extrapyramidal side effects compared with older, purely D2-blocking agents. In short, aripiprazole’s mixed dopaminergic and serotonergic actions define its atypical profile, whereas typical antipsychotics are strong D2 antagonists with higher EPS risk. (Risperidone is also atypical, but the material highlights aripiprazole for its unique partial-agonist mechanism.)