Which antipsychotic drug is least likely to cause metabolic syndrome?

Haloperidol is an antipsychotic that belongs to the class of typical or first-generation antipsychotics. It is less likely to cause metabolic syndrome compared to the atypical or second-generation antipsychotics listed in the other options.

Metabolic syndrome is characterized by weight gain, dyslipidemia, insulin resistance, and hypertension, and is a common side effect associated with many second-generation antipsychotics such as olanzapine, quetiapine, and risperidone. These agents are more likely to interfere with metabolic processes, leading to increased body weight and changes in glucose and lipid metabolism.

In contrast, haloperidol primarily acts as a dopamine D2 receptor antagonist, and its side effect profile tends to include more extrapyramidal symptoms rather than the metabolic disturbances often seen with atypical antipsychotics. Therefore, haloperidol is viewed as having a lower risk for metabolic syndrome, making it the least likely among the provided options to contribute to this condition.