Substantial levels of dopamine D2 receptor occupancy, ranging from 53% to 74%, were found with doses of 2 mg/day of haloperidol (2). In another PET study (3), 2–5 mg/day of haloperidol led to dose-dependent plasma levels from 0.5 to 5.8 ng/ml and to 53%–88% D2 receptor blockade. Accordingly, an [123I]iodobenzamide SPECT study also revealed a dose-dependent striatal D2 receptor occupancy of 63%–85% with 5–20 mg/day of haloperidol (4). In summary, those data suggest that it may not be wise to use daily doses of more than 10 mg of haloperidol. Clinical experience in schizophrenia supports this view. We are aware that the cited data were obtained from patients with schizophrenia. However, it is only fair to assume that nonschizophrenic patients would need approximately the same or even lower doses to establish antipsychotic efficacy. At this level, brain D2 receptors are most likely already saturated, so patients receiving higher doses are at high risk for more and unnecessary side effects. In cases of severe delirium that is unresponsive to an equivalent of 10 mg/day of haloperidol, one might consider the addition of substances with different mechanisms of action, e.g., glutamatergic or γ-aminobutyric acid medications.