A Study to Investigate the Efficacy, Safety and Tolerability of Four Different Doses of BI 409306 Compared to Placebo Given for 12 Weeks in Patients With Schizophrenia on Stable Antipsychotic Treatment.

Taipei City Hospital, Taipei

Chang-Hua Christian Hospital, Changhua

NCKUH, Tainan City

Kai-Syuan Psychiatric Hospital, Kaohsiung City

Richmond Behavioral Associates, Staten Island

Neurobehavioral Research, Inc., Cedarhurst

Finger Lakes Research, Rochester

University of Rochester Medical Center, Rochester

Comprehensive Clinical Development, Washington D.C.

Atlanta Center, Atlanta

Florida Clinical Research Center, Maitland

Behavioral Clinical Research, Inc., North Miami

Innovative Clinical Research, Lauderhill

LVR-Klinikum Düsseldorf, Düsseldorf

Universitätsklinikum Köln (AöR), Cologne

Northwestern University, Chicago

Uptown Research Institute, Chicago

Mid-America Clinical Research, LLC, St Louis

St. Louis Clinical Trials, St Louis

Uniklinikum Heidelberg, Heidelberg

Lake Charles Clinical Trials LLC, Lake Charles

K and S Professional Research Services, LLC, Little Rock

InSite Clinical Research, DeSoto

Community Clinical Research, Inc., Austin

Pacific Institute of Medical Research, Los Angeles

Collaborative Neuroscience Network, Torrance

Comprehensive Clinical Development, Inc., Cerritos

SRSD, Inc. dba Synergy San Diego, National City

Artemis Institute for Clinical Research, LLC, San Diego

Collaborative Neuroscience Network, Garden Grove

NRC Research Institute, Orange

Dr. Alexander McIntyre Inc., Penticton

Depression, Mood Disorders and Schizophrenia Treatment Centr, Burlington

Fujita Health University Hospital, Aichi, Toyoake

Hokkaido University Hospital, Hokkaido, Sapporo

Kobe University Hospital, Hyogo, Kobe

Nara Medical University Hospital, Nara, Kashihara

Kansai Med. Univ. Med. Ctr., Osaka, Neuropsychiatry, Osaka, Moriguchi-city

Hizen Psychiatric Center, Saga, PSY, Saga, Kanzaki-gun

Iwaki Clinic, Tokushima, Psychosomatic Medicine, Tokushima, Anan

National Center Neurology and Psychiatry, Tokyo, Kodaira

Showa University Karasuyama Hospital, Tokyo, Setagaya

Showa University East Hospital, Tokyo, Shinagawa