 1.2 Objective. This project proposes to examine how caffeine alters ERP-indexed aspects of cognition in SZ patients. Neural ERPs and behavioural hits, reaction time correlates of cognitive performance will be probed within a randomized, double-blind, placebo-controlled design with a battery of well-established cognitive paradigms that have both demonstrated deficits in SZ and are associated with caffeine-induced enhancement: a visual selective attention paradigm visual search task, a working memory paradigm N-back, and a sustained attention paradigm AX-CPT. The primary outcome measures will be ERP amplitudes and latencies. Secondary indices will include behavioural measures of performance, including accuracy correct, reaction times and measures of signal detection i.e. d. While the investigators expect caffeine to improve behavioural and neural indices in both groups, the investigators expect this effect to be stronger in SZ patients due to expected lower baselines. 