This PoC study is designed to assess the cognitive effects of doses of AQW051 in patients with chronic stable schizophrenia.

Inclusion Criteria:

1. Diagnosis of schizophrenia
2. Symptomatically stable and currently treated with a stable regimen for at least 3 (three) months prior to dosing with one of the following second generation of antipsychotics: risperidone, paliperidone, quetiapine, ziprasidone, aripiprazole.
3. Specific cognitive impairment
4. Smokers and non-smokers

Exclusion Criteria:

1. Current treatment with an anticholinergic or other agent known to adversely interfere with the cholinergic system, and/ or treatment with cholinesterase inhibitor within the last three (3) months prior to dosing.
2. Current treatment with conventional antipsychotics (e.g fluphenazine, haloperidol) or clozapine.
3. History of neuroleptic malignant syndrome.
4. Diagnosis of substance abuse (other than nicotine) within the last month and alcohol or substance dependence (other than nicotine) within the last 6 months.
5. Any clinically significant suicidal ideation (Type 4 or 5 on the Columbia-Suicide Severity Rating Scale (C-SSRS) in the last month) or previous history of suicide behavior Other protocol-defined inclusion/exclusion criteria may apply