The main purpose with the study is to explore the efficacy and safety of Lu 31-130 in patients suffering from schizophrenia compared to a standard antipsychotic drug.

Schizophrenia is a serious and disabling mental disorder that affects approximately 1% of the world's population. Antipsychotic drugs remain the cornerstone in the pharmacotherapy of schizophrenia. However, none of the available drugs is ideal, in particular because of their complex safety profile and the limited effectiveness against certain symptom domains. Whereas positive symptoms respond to treatment the effects on negative symptoms and cognitive impairment are only very modest.

Thus present treatment options leave room for improvement and call for new, more effective pharmacotherapies for the treatment of schizophrenia. In the current study, patients suffering from schizophrenia and experiencing clinically significant symptoms of the disease will be included. Eligible patients will be randomised to blinded treatment with either flexible doses of Lu 31-130 or flexible doses of a standard antipsychotic treatment (olanzapine) for 12 weeks. The efficacy (including potential effects on cognitive symptoms) and the safety of Lu 31-130 will be explored in comparison to olanzapine.

Inclusion Criteria:

• The subject has a primary diagnosis of schizophrenia
• The subject experiences clinically significant symptoms
• The subject is willing to be hospitalized during the initial period of the study
• The subject has normal serum values of parameters associated with liver function