STRESS-SLEEP RELATIONSHIPS IN PATIENTS WITH SCHIZOPHRENIA SPECTRUM DISORDERS AND THE MODERATING ROLE OF PSYCHIATRIC CORRELATES

Abstract

Background: The relationship between stress and sleep has been well established, evidencing bidirectionality in that elevated stress can lead to sleep disruptions, and prolonged sleep problems can lead to a greater stress response. Stress experiences are not homogeneous and instead can present in different forms consisting of acute, chronic and/or early life exposures. Both stress and sleep can be categorized as objective (e.g., biological measures, reported count of stressors experienced) and subjective (e.g., perceived severity). While separately, stress and sleep disruptions are well studied in patients with schizophrenia spectrum disorders (SSD), the relationship between sleep and stress, particularly stress types (i.e., acute, chronic, early life), along with both objective and subjective data in these disorders has yet to be comprehensively examined.

Purpose: The purpose of this study was to examine the relationships between acute, chronic, and early life stress and sleep quality in patients with SSD and in healthy individuals using both objective and subjective measurement methods, and to determine whether these relationships were stronger in the SSD group. The influence of increased psychiatric symptoms (i.e., positive and negative psychotic symptoms) as a moderator of stress-sleep relationships were examined as well.

Methods: A total of 130 individuals participated in the study, which included 87 patients with SSD and 43 healthy individuals. Sleep was measured using Pittsburg Sleep Quality Index (PSQI) and by using sleep overnight EEG recordings. Stress was measured using the Stress and Adversity Inventory (STRAIN), Perceived Stress Scale (PSS), Childhood Trauma Questionnaire (CTQ), and the Allostatic Load Index. Psychiatric symptoms were measured using the Brief Psychiatric Rating Scale (BPRS). Age and sex were included covariates when examining stress-sleep relationships.

Results: Results revealed that patients with SSD displayed significantly elevated stress levels across objective and subjective measures, as well as poorer sleep quality and sleep architecture disturbances measured by sleep EEG compared to healthy individuals. While there was a positive relationship between objective and subjective acute stress and sleep quality in patients with SSD, this was not found in healthy individuals. In contrast, greater exposure to chronic objective and subjective stress was generally associated with poorer sleep quality in the healthy individuals but not in the SSD patient group. Greater exposure to both objective and subjective early life stress was generally associated with poorer sleep quality in the SSD patients. Psychiatric symptoms did not moderate any of the stress-sleep relationships. Finally, the relationship between stress and disruptions of objective sleep parameters mostly emerged in the SSD group.

Discussion: The results indicated varying patterns in stress-sleep quality relationships in patients with SSD and healthy individuals, with psychiatric symptoms not moderating these relationships. The findings highlight the importance of personalized and stress specific interventions to address sleep problems in patients with schizophrenia spectrum disorders.