P037 The effects of obstructive sleep apnea on cognition in schizophrenia

Abstract Schizophrenia diagnosis relies primarily on clinical assessment, the ability to track cognitive function thus becomes an important tool in assessing symptom severity and the effects on daily function. As a result of medications, obstructive sleep apnea (OSA) risk in schizophrenia is high. As the impact of OSA in schizophrenia is unclear, we aimed to measure cognitive performance in schizophrenia and whether further impairments in performance are seen in patients with OSA. As per in OSA populations, we hypothesise sleep disruption due to OSA may not explain cognitive performance in schizophrenia. Participants in two groups 1) people with schizophrenia (n = 31) and 2) without schizophrenia (n = 31) with similar group level AHI severity and matched for age and sex completed cognitive tasks before polysomnography (PSG) with high density EEG. Sleep dependent procedural and declarative memory tasks were before and after sleep as well as tasks measuring vigilance, executive function and planning before sleep. We used general linear models to investigate the effects of group and OSA and its interaction on cognitive performance. Significant group differences in cognitive performance in the schizophrenia was observed in the measures of procedural memory (β -21.6,p<.05) reaction time (β -0.8,p<.05), planning (β 10.5,p<.05) executive function in the Stroop Colour only (β -19.5,p<.05). Across all tasks, AHI and ODI did not further impair cognitive performance across both groups.(p>.05). Our results suggest that OSA does not further impact cognitive performance in schizophrenia. Future work will examine the role of sleep architecture on OSA severity and its role in cognition.