A Study to Evaluate ABT-126 for the Treatment of Cognitive Deficits in Schizophrenia

This is a Phase 2 study designed to evaluate the safety and efficacy of ABT-126 in treating
cognitive deficits in subjects with a diagnosis of schizophrenia. Eligible subjects will
take study drug as an add-on treatment to their ongoing antipsychotic treatment regimen.

Inclusion Criteria:

- Has a current Diagnostic and Statistical Manual of Mental Disorders-, 4th Edition,
Text Revision (DSM-IV-TR) diagnosis of schizophrenia confirmed by the
Mini-International Neuropsychiatric Interview (M.I.N.I.).

- Is clinically stable while receiving a regimen of one or two allowable antipsychotic
medications: lack of hospitalizations in 4 months prior to initial screening visit;
taking the same antipsychotic medication(s) for at least 8 weeks prior to baseline
visit; core positive symptoms of Positive and Negative Syndrome Scale (PANSS) no
worse than moderate in severity throughout screening period of at least 4 weeks.

- Has been diagnosed with or treated for schizophrenia for at least 2 years prior to
initial screening visit.

- Has had continuity in psychiatric care (e.g., mental health system, clinic or
physician) for at least 6 months prior to initial screening visit.

- Has an identified contact person (e.g., family member, social worker, case worker, or
nurse) that can provide support to the subject to ensure compliance with protocol
requirements.

Exclusion Criteria:

- In the Investigator's judgment, has a current or past diagnosis of schizoaffective
disorder, bipolar disorder, manic episode, dementia, post traumatic stress disorder,
or obsessive-compulsive disorder, or the subject has a current major depressive
episode.

- Has a positive urine drug screen for cocaine, phencyclidine (PCP), opiates (unless
duly prescribed), benzodiazepines (unless duly prescribed), marijuana, or
amphetamines during the Screening Period.

- Has a current or past history of seizures, with the exception of a single febrile
seizure occurring prior to 6 years of age.

- Has a clinically significant abnormal electrocardiogram (ECG) at Screening Visit 1 as
determined by the Investigator.

- Has any risk factors for Torsades de Pointes (TdP)