The primary purpose of this study is to determine whether a combination of ACP-103 (the study medication) with either haloperidol or risperidone will show antipsychotic efficacy and that it is safe and well tolerated. Further purposes of this study are to determine whether ACP-103, in combination with either haloperidol or risperidone, will enhance their antipsychotic effectiveness, demonstrate effectiveness against the negative symptoms, improve motoric tolerability, and is safe and well tolerated.