PDE10A and schizophrenia: Continuing along this line, most of the patients in our study were treatment-resistant and therefore treated with clozapine; the others were treated with other diazepines with a similar, but not as marked balance between striatal D1 and D2 receptor occupancy.41 This might explain why we observed a lower BPND of PDE10A in patients with schizophrenia, whereas Marques et al.16 did not, as they studied patients treated with other, more D2-receptor-antagonistic antipsychotics.