Which of the following is considered a first generation antipsychotic?

Haloperidol is classified as a first-generation antipsychotic, also known as a typical antipsychotic. These medications primarily function by blocking dopamine D2 receptors in the brain, which is effective in managing symptoms of psychosis, such as delusions and hallucinations. Haloperidol has been widely used in the treatment of schizophrenia and acute psychotic episodes due to its established efficacy.

The other medications mentioned are second-generation antipsychotics, which work through a different mechanism and have a broader spectrum of action. For instance, aripiprazole and quetiapine mainly influence both dopamine and serotonin receptors, which can help alleviate both positive and negative symptoms of schizophrenia. Clozapine, while also effective, is known for its unique side effect profile and is generally reserved for treatment-resistant cases. Understanding the distinctions between these generations of antipsychotics is crucial for appropriate treatment selection based on individual patient needs and responses to therapy.