To evaluate the safety and tolerability of multiple doses of PF-02545920 subjects with schizophrenia or schizo-affective disorder who are currently clinically stable and to evaluate the serum and urine pharmacokinetics of PF-02545920 and the N-desmethyl metabolite, PF-01001252, after multiple doses of PF-02545920 administered orally.

Inclusion Criteria:

• Subjects with DSM-IV diagnosis of schizophrenia or schizo-affective disorder for whom antipsychotic monotherapy is indicated.
• Subjects must be free from an acute exacerbation of psychosis for at least 3 months prior to screening.
• Current Clinical Global Impression (CGI) of Severity of Illness score ≤ 3.

Exclusion Criteria:

• Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, neurological, or allergic disease (including drug allergies, but excluding untreated, asymptomatic, seasonal allergies at time of dosing).
• Evidence or history of a primary DSM-IV axis I diagnosis other than schizophrenia or schizoaffective disorder.
• Any condition possibly affecting drug absorption (e.g., gastrectomy).