Abnormalities in sleep patterns in individuals at risk for psychosis and bipolar disorder

Abstract

Aim: To compare patterns of sleep and the presence of sleep disturbances in individuals in at-risk mental states (ARMS) for psychosis and bipolar disorder (BD) with a healthy control (HC) group.

Methods: This was a comparative study involving 20 individuals in ARMS for psychosis or BD, according to the Comprehensive Assessment of At-Risk Mental States, and 20 age- and sex-matched healthy controls. Quality of sleep in the previous month was assessed using the Pittsburgh Sleep Quality Index, diurnal somnolence was evaluated using The Epworth Sleepiness Scale, and chronotype was determined using the Questionnaire of Morningness/Eveningness (QME). All of the participants underwent polysomnography (PSG) during the entire night for two consecutive nights. The first night aimed to adapt the subject to the environment, and only the data from the second night were used for the analysis.

Results: Compared with the HC group, individuals in the ARMS group reported significantly worse sleep quality, as measured by the Pittsburgh Sleep Quality Index. Both groups had scores consistent with daytime sleepiness on the Epworth Sleepiness Scale, and there were no differences with regard to chronotype between the groups, with a predominance of the indifferent type in both groups. In the PSG assessment, we observed increased Sleep Latency (SL) and increased Rapid Eye Movement Sleep Onset Latency (REMOL) in the ARMS group, compared to the HC group.

Conclusion: The results of this study indicated that sleep abnormalities could be found early in the course of mental diseases, even in at-risk stages, and support the further investigation of their predictive value in the transition to psychosis and BD.

Keywords: At-risk mental states; Bipolar disorder; Early stages; Polysomnography; Prodromal; Psychosis; Schizophrenia; Sleep.