Olanzapine possesses a broad pharmacological profile, interacting with a ra
nge of different neurotransmitter receptors. Although its affinity for musc
arinic receptors is relatively greater than for dopamine receptors, on sche
dule-controlled behaviour olanzapine displays a profile resembling a dopami
ne antagonist. Likewise, in a test of cognitive function, olanzapine does n
ot produce anticholinergic-like deficits. In drug discrimination assays, ol
anzapine substitutes for clozapine in clozapine-trained animals and clozapi
ne generalises to olanzapine in olanzapine-trained animals. Olanzapine also
reverses the behavioural deficits produced by inhibiting N-methyl-D-aspart
ate receptor glutamatergic transmission. This profile suggests that olanzap
ine will be effective against both positive and negative symptoms of schizo
phrenia while producing minimal extrapyramidal side-effects.