Definition clozapine starters and stable users

Start of clozapine was defined as a first clozapine prescription with no evidence of a clozapine prescription for at least 1 month before, followed by a gradual dose escalation resulting in a dose of at least 50 mg once daily within the subsequent 7 days. Participants were followed until they were defined as stable users or stopped clozapine therapy. Stable clozapine users were defined as patients with a medication order for clozapine where the prescribed dose remained unchanged for at least 5 consecutive days or information in the patient records explicating continuing of same dose for at least 5 days, as it was expected that clozapine PK reached steady state after 5 days.