Letters Section Editor: Stephen J. Lurie,
MD, PhD, Senior Editor.
To the Editor: We have 2 concerns about the
study by Dr Rosenheck and colleagues.1 First,
the average dosages of olanzapine (14.1 mg/d) and haloperidol (13.6 mg/d)
do not reflect similar levels of dopamine D2 receptor occupancy
in each treatment group: about 75% for olanzapine and about 90% for haloperidol.2 Although the dosages that the authors used are
common in practice, they do not reflect optimal dosing for haloperidol. Given
the relationship between dopaminergic neurotransmission and extrapyramidal
symptoms and aspects of cognitive and motor functioning,3 differences
in dopamine D2 receptor occupancy could partially explain the small
advantages found in favor of olanzapine.
de Haan L, van Beveren N. Olanzapine vs Haloperidol for Treatment of Schizophrenia. JAMA. 2004;291(9):1064. doi:10.1001/jama.291.9.1065-c