Study to Evaluate the Efficacy and Safety of GSK239512 in Schizophrenia

This is a 7-week, Phase II, multi-centre, randomised, double-blind, placebo-controlled,
parallel group design study in male and female subjects with schizophrenia who are stabilised
on antipsychotic medication. Subjects will be randomised to receive either GSK239512 or
placebo for 7 weeks. They will undergo weekly review of safety, tolerability and cognitive
performance measures.

Inclusion Criteria:

1. Clinical diagnosis of Schizophrenia

2. No acute exacerbation of symptoms requiring hospital admission or step up care in the
previous six months.

3. Not on any symptomatic treatment for cognition

Exclusion Criteria:

1. Poses a significant homicidal or suicidal risk or evidence of previous homicidal or
suicidal risk.

2. Co-morbid psychiatric or significant physical illness

3. Alcohol or drug abuse or dependence.