This is a first-in-human study of JNJ-40411813 in schizophrenic patients who are not currently receiving antipsychotic drug treatment (referred to as "(sub) acute" patients) and in patients who are currently taking antipsychotic drug treatment (referred to as "stable" patients). The study will consist of 2 parts: Part A and Part B. Part A will be open-label (patients will know the identity of study treatment), and (sub)acute schizophrenic patients will receive monotherapy (treatment with one drug) with JNJ-40411813. Part B will be double-blind (patient and study staff will not know the identity of study treatment) and will randomize (assign by chance) patients with stable but symptomatic schizophrenia to receive treatment with JNJ-40411813 or a placebo (treatment identical in appearance to JNJ-40411813 but does not contain active drug) as add-on therapy to their currently prescribed antipsychotic medication. Parts A (JNJ-40411813 monotherapy) and B (JNJ-40411813 add-on therapy) will run simultaneously. Patients will take JNJ-40411813 and placebo capsules orally (by mouth) twice daily (bid) with a meal. Part A: Patients will take JNJ-40411813 50 mg (1 capsule) bid up to 150 mg (3 capsules) bid for up to 12 weeks. Part B: Patients will take JNJ-40411813 50 mg bid or placebo bid for 4 weeks. After 4 weeks, the dose of JNJ-40411813 may be increased up to 150 mg bid for 6 weeks, and patients assigned to placebo may take JNJ-40411813 50 mg bid to 150 mg bid for up to 10 weeks.
