The ELAN study is a prospective multi centre observational trial on the effectiveness and safety of long-term antipsychotic treatment of people with schizophrenia or schizoaffective disorders with quetiapine in comparison to olanzapine and risperidone under real world treatment conditions.

374 adult persons with schizophrenia or schizoaffective disorder prescribed antipsychotic maintenance therapy with quetiapine, olanzapine or risperidone were included at discharge from inpatient treatment. Psychotropic regimen, psychopathological symptoms, general and cognitive functioning, negative side-effects and quality of life were assessed before discharge and at 6, 12, 18 and 24 month follow-up assessments. Intention-to-treat analyses and crossover analyses were conducted by mixed-effects regression models including random linear time effects and time x treatment effects, controlling for baseline differences and additional psychotropic medication and using propensity scores to control for selection bias.

As indicated by significant linear time effects the patients improved with regard to psychopathological symptoms, general functioning, subjective quality of life and cognitive processing speed. No change of extrapyramidal motor side-effects, body mass index or waist circumference was obtained. The lack of any significant time x treatment interaction effects indicated no differences in the safety or effectiveness between the three antipsychotics. Nevertheless, the average hospital admission rate of patients receiving olanzapine was lower in comparison to patients receiving quetiapine or risperidone.