Rest-activity rhythm disruption and metabolic health in schizophrenia: a cross-sectional actigraphy study of community-dwelling people living with schizophrenia and non-psychiatric comparison participants.

STUDY OBJECTIVES: People living with schizophrenia (PLWS) have increased physical comorbidities and premature mortality which may be linked to dysregulated rest-activity rhythms (RARs). This study aimed to compare RARs between PLWS and non-psychiatric comparison participants (NCs); examine the relationships of RARs with age, sleep, metabolic and physical health outcomes; and, among PLWS, relationships of RARs with illness-related factors.

METHODS: The study sample included 26 PLWS and 36 NCs, assessed with wrist-worn actigraphy to compute RAR variables and general sleep variables. Participants completed assessments for clinical symptoms, physical health, sleep quality, medication use, and assays for fasting glycosylated hemoglobin (HbA1c) levels. We examined group differences in RAR and sleep variables, relationships of RAR variables with metabolic and physical health measures, and, among PLWS, relationships between RAR variables and illness-related measures.

RESULTS: PLWS had significantly shorter active periods, lower relative amplitude, and lower mean activity during their most active 10 hours compared to the NCs (Cohen's d =.79, .58, and .62; respectively). PLWS had poorer sleep quality, greater mean percent sleep, less wake after sleep onset, and higher total sleep time (TST) variability compared to NCs. PLWS had higher rates of antidepressant, anxiolytic, and antipsychotic medication use compared to NCs, which may have impacted sleep quality and objective sleep measures. Across both groups, more fragmented and variable RARs were associated with higher HbA1c levels ( ηp 2 =0.10) and worse physical health ( ηp 2 =0.21). Among PLWS, RARs were correlated with TST ( rs =.789, p <0.01) and percent sleep ( rs =.509, p <0.05), but not with age, sleep quality, or other illness-related factors.

CONCLUSIONS: RARs provide unique information about sleep and activity for PLWS and have the potential for targeted interventions to improve metabolic health and mortality.