This is a double-blind placebo-controlled trial to evaluate the effects of the combination of a cognition enhancing drug, i.e carnosine, with cognitive training in patients with schizophrenia. All participants will receive the same cognitive training sessions and will be randomised to either carnosine or placebo for the duration of the combined treatment period (2 weeks). Before combined training and carnosine/placebo, there is a two-week carnosine/placebo only phase to examine the effects of carnosine alone on functioning without training.