The purpose of this study is to evaluate the effects of nicotinic alpha-7 MEM 3454 on P50 sensory gating in patients with Schizophrenia. The hypothesis is that MEM 3454 will normalize the P50 ratio.

Data produced in this study will provide useful information regarding the value of P50 as an efficacy biomarker, and provide evidence for the optimal dosing of MEM 3454 for additional P50 studies.

Inclusion Criteria:

• 1. Male or female subjects between 18and 55 years of age.
• 2. Fluent in English, even if English is not the primary language.
• 3. Able to provide informed consent.
• 4. DSM IV-R primary diagnosis of schizophrenia (any subtype), assessed using a structured diagnostic interview (SCID CT).
• 5. Few or no extra-pyramidal symptoms(EPS)at screening,defined as SAS < 6.
• 6. Negative urine drug screen (UDS).
• 7. Negative cotinine test.
• 8. Clinically stable, as judged by the investigator, and in a non-acute phase for at least 12 weeks. At least one month on the same dose of antipsychotic medication.

Exclusion Criteria:

• Current risk of suicide, or history of suicidal behavior within the last 6 months.
• Hospitalized for psychiatric symptoms in the past 3 months.
• Other psychiatric diagnoses.
• Substance abuse/dependence (other than nicotine or caffeine) within the last 6 months according to the SCID-CT.
• Currently smoking, nicotine replacement therapy, smoking cessation medications or remedies, including Varenicline (Chantix).
• Any medical condition, as judged by the Investigator, which may interfere with the subjects' participation in this study.