Background The efficacy and safetyof long-acting injectable risperidone have not been comparedwiththose of an oral atypical antipsychotic. Aims To compare long-acting risperidone and oral olanzapine in 377 patientswith DSM^IV schizophrenia

Declaration of interest N.K. has received support fromorbeen a consultant for AstraZeneca,BristolMeyers Squibb,Janssen Pharmaceutica,Eli Lilly, Sanofi-Synthelabo,Pfizer andWyeth. M.I.,A.K. and K.K. are employees of Johnson & Johnson. The efficacy and safety of long-acting injectable risperidone have been evaluated in several trials of patients with schizophrenia or schizoaffective disorder, including a 12-week, double-blind, placebocontrolled study (n1⁄4554; Kane et al, 2003) and a 12-month open-label trial (n1⁄4615; Fleischhacker et al, 2003). The effectiveness of long-acting risperidone has also been demonstrated in patients switched from typical and atypical oral antipsychotic medication (Lindenmayer et al, 2004; Chue et al, 2005) and from conventional depot antipsychotics (Turner et al, 2004). In the 12-week double-blind study by Chue et al (2005), long-acting risperidone was compared with oral risperidone in patients with schizophrenia. Both treatments were efficacious and well tolerated. According to a non-inferiority analysis, the two treatments showed comparable efficacy in Positive and Negative Syndrome Scale (PANSS; Kay et al, 1987) total scores over the short term. Long-acting risperidone, however, has not been compared with an oral formulation of another atypical antipsychotic such as olanzapine. In this 53week, open-label, randomised controlled international study (registered with the US National Institutes of Health at http://clinicaltrials.gov as NCT00236457) we compared long-acting risperidone with olanzapine tablets in patients with schizophrenia or schizoaffective disorder. The objectives of the study were, first, to demonstrate that in the short term long-acting injectable risperidone was at least as effective as (not inferior to) oral olanzapine in patients with schizophrenia or schizoaffective disorder. Non-inferiority would be demonstrated if, at the end of the initial 13-week treatment period, the upper limit of the confidence interval for the difference in mean change from baseline in PANSS total scores was not more than 8 points in favour of oral olanzapine. The second objective was to examine the longterm efficacy and safety of long-acting risperidone and oral olanzapine in these patients.