The purpose of this study is to determine whether treatment with daily oral dose of AZD8529 40 mg administered over 28 days is safe, well tolerated and improves main symptoms of schizophrenia in adult schizophrenia patients.

Inclusion Criteria:

• Patient will need to read, understand and sign an informed consent prior to any study specific procedures
• Patient will have certain schizophrenia symptoms deemed by the investigator as appropriate for the study entry

Exclusion Criteria:

• Patients will be excluded based on recent history of significant illness or current disease as assessed by the investigator during screening process (based on physical examination, laboratory studies and electrocardiogram studies)
• Patients will be excluded if urine drug screen test show positive results
• Smoking of more than 2 packs of cigarettes a day