Add On Treatment for Cognitive Deficits in Schizophrenia

All participants will receive 3 weeks of PF-03654746 and 3 weeks of placebo. PF-03654746 and placebo will be administered in a flexible titration regimen, beginning with 0.5 mg/d. If 0.5 mg/d is well tolerated, the dose will be increased to 1.0 mg/d after 5 days. If 1.0 mg/d is not well tolerated, the dose will be decreased to 0.5 mg/d, with the goal of achieving a stable dose of PF-03654746 within the first two weeks of dosing and avoiding further dose changes during the final week of dosing.

Placebo will be used as a comparator to the active arm.