Among the listed antipsychotics, which has the highest risk of extrapyramidal symptoms?

Haloperidol is known for its high propensity to cause extrapyramidal symptoms (EPS), which are drug-induced movement disorders, including tremors, rigidity, bradykinesia, and tardive dyskinesia. As a typical antipsychotic, Haloperidol primarily works by blocking dopamine D2 receptors in the central nervous system. This blockade, particularly in the nigrostriatal pathway, is strongly associated with the development of EPS.

In contrast, the other antipsychotics listed have a comparatively lower risk of causing these symptoms. Thioridazine and Chlorpromazine can induce EPS but to a lesser extent than Haloperidol. Quetiapine, as an atypical antipsychotic, has a substantially lower incidence of EPS due to its action on multiple neurotransmitters, including serotonin, which helps mitigate the risk of movement disorders.

Hence, Haloperidol is recognized in clinical practice as having the highest risk among the antipsychotics listed for causing extrapyramidal symptoms, making it a critical consideration when prescribing treatment for patients, especially those vulnerable to such side effects.