SPECT Study With SB-773812 In Schizophrenic Patients

Inclusion criteria: * schizophrenic patients as diagnosed by DSM IV criteria. * In group 2, subject has schizophrenia or schizophreniform disorder and show moderate disease exacerbation, a PANSS score \> 65 and a score in the PANSS positive scale (PANSS-P) =25. * Women of childbearing potential must agree to acceptable method of birth control. Exclusion criteria: * Subject shows severe exacerbation, extreme instability, high risk for suicide or serious violent behaviour. * Any clinically or laboratory significant abnormality. * Subjects receiving a radiation dose from other activities of more than 10 mSv over any 3 year period. * Subjects with organic brain disease and history of severe head trauma. * Heart pacemaker, metallic prosthesis or other metallic body implants. * Significant head deformity. * Smokers with associated COPD. * History or presence of clinically significant gastro-intestinal, hepatic or renal disease. * History of cholecystectomy or biliary tract disease. * Positive for HBV, HCV or HIV. * Pregnant or lactating women.