Inclusion Criteria:

• Subjects or guardian must be willing to give written informed consent.
• Part 1 Only: Subjects with acute (not drug related) psychoses with a PANSS score of at least 60: schizophrenia, schizo-affective, schizo-manic, and acute mania with a history of previous treatment with neuroleptics.
• Part 1 Only: Subjects initiating haloperidol for the treatment of an acute psychotic episode at a dose of at least 7.5 mg per day.
• Part 2 Only: Inpatient subjects who have developed akathisia as a result of haloperidol at >=5 mg per day for the treatment of acute psychosis. The enrollment of subjects receiving other neuroleptics is allowed only after consultation and agreement by the sponsor.
• Subjects of either sex and of any race between the ages of 18 and 65 years, inclusive.
• Subjects' clinical laboratory tests (CBC, blood chemistry, and urinalysis) must be within normal limits or clinically acceptable to the investigator/sponsor. Subject's liver function test results (ie, AST, ALT) must not be elevated above the normal limits at Screening and on Day -1/1.
• Subjects must be free of any clinically significant disease other than psychosis that would interfere with the study evaluations.
• Screening ECG must be clinically acceptable to the investigator.

• Female of childbearing potential must:

  • Have used a medically accepted method of contraception for 1 month (or abstained from sexual intercourse) prior to the screening period. An acceptable method of contraception includes one of the following:

    • condom (male or female) ~ spermicide,
    • diaphragm or cervical cap ~ spermicide and condom,
    • stable oral/transdermal/injectable hormonal contraceptive regimen without breakthrough uterine bleeding for 2 months prior to Screening visit and a condom ~ spermicide,
    • intrauterine device (inserted at least 2 months prior to Screening visit) used spermicide.

Note: Vasectomy of the partner is not considered sufficient contraception and one of the 4 bulleted methods listed above must be used.

• Agree to use one of the accepted methods of contraception (listed above) during the trial (including the screening period prior to receiving trial medication), and for 1 month after stopping the trial medication.
• Subjects enrolled in the placebo arm of Part 1 and who developed akathisia may be eligible for Part 2 in the standard of care arm.

Exclusion Criteria:

• Subjects who have a positive screen for drugs with a high potential for abuse. Subjects that screen positive for cannabis are permitted.
• Subjects who have previously received this compound.
• Subjects who are currently participating in another clinical study or have participated in a clinical study within 30 days (excepted subjects enrolled in the Part 1 of the P05145 study).
• Subjects who are part of the study staff personnel or family members of the study staff personnel.
• Subjects with severe/uncontrolled hypertension will be excluded. Subjects with hypertension well controlled on a stable dose of standard antihypertensive medication (excluding beta-blockers) will be eligible.
• Subjects with history of coronary artery disease including MI, or cerebrovascular disease (stroke, TIA), or peripheral arterial disease.
• Subjects with congestive heart failure or subjects with ECGs consistent with ischemic heart disease, sick sinus syndrome or significant Q waves.
• Subjects who are found to be at immediate risk of suicide.
• Female subjects pregnant or nursing.
• Subjects treated by Clozapine will be excluded. A washout period of 6 months prior to dosing will be acceptable for study entry.