The purpose of this study is to demonstrate that AZD3480 improves cognition in patients with stable schizophrenia who are being treated with an atypical antipsychotic and who are active cigarette smokers, to assess the safety and tolerability of AZD3480 and to define the optimal dose(s) to be used in future trials.

Inclusion Criteria:

• Diagnosis of schizophrenia
• Outpatient at the time of screening and randomization
• Stable housing defined as having a place to live in the community (ie, not in a hospital or nursing home)
• Active cigarette smoking (10 or more cigarettes per day

Exclusion Criteria:

• Any significant psychiatric or neurological disease other than schizophrenia, or current diagnosis of major depressive disorder
• Known or suspected drug or alcohol abuse within the 6 months or urine toxicology test positive for illegal or non-prescribed substances
• Impaired vision and/or hearing making cognitive testing difficult