Latent sleep disturbance consists of significant time-invariant and time-varying components (with the time-invariant component accounting for most variance at 82.7%), and between-person components of sleep disturbance and psychological distress were moderately positively correlated, though within-person deviations did not prospectively predict one another on a month-to-month basis.
Key Findings
Results
Latent sleep disturbance is predominantly characterized by a time-invariant (trait) component, which accounted for 82.7% of the variance over a 5-month period.
Study sample consisted of N = 862 community adults observed over a 5-month period.
Sleep disturbance was indexed by three indicators: sleep efficiency, perceived sleep quality, and daily disturbances.
The time-invariant component accounted for 82.7% of the variance in latent sleep disturbance.
Both time-invariant and time-varying components were statistically significant, indicating that sleep disturbance has meaningful stable and fluctuating dimensions.
Results
Between-person components of latent sleep disturbance and latent psychological distress were moderately positively correlated.
The between-person (trait-level) correlation between latent sleep disturbance and latent psychological distress was r = .56.
This association was identified using a random intercept cross-lagged panel model (RI-CLPM), which separates stable between-person differences from dynamic within-person processes.
The moderate positive correlation suggests individuals who tend to sleep worse also tend to report higher psychological distress on average.
Results
Within-person deviations in latent sleep disturbance and latent psychological distress did not prospectively predict one another on a month-to-month basis.
The RI-CLPM was applied to separate trait-level from state-level (within-person) dynamics over 5 months.
Both latent variables were stable over the 5-month period within individuals.
Month-to-month within-person fluctuations in sleep disturbance did not predict subsequent within-person fluctuations in psychological distress, and vice versa.
This finding suggests the prospective within-person relationship between sleep disturbance and psychological distress may not operate on a monthly timescale.
Results
Significant concurrent covariation was observed between latent sleep disturbance and latent psychological distress within individuals, and this association increased modestly over time.
Within-person concurrent (same time point) covariation between sleep disturbance and psychological distress was statistically significant.
The strength of the concurrent within-person association between sleep disturbance and psychological distress increased modestly across the 5-month observation period.
This pattern of concurrent but not prospective within-person association distinguishes state-level from trait-level dynamics.
Methods
A random intercept cross-lagged panel model (RI-CLPM) was used to disentangle trait-level and state-level associations between sleep disturbance and psychological distress.
The RI-CLPM allows separation of stable between-person differences (trait-level) from dynamic within-person processes (state-level).
Sleep disturbance was modeled as a latent variable using sleep efficiency, perceived sleep quality, and daily disturbances as indicators.
Psychological distress was also modeled as a latent variable.
The study spanned 5 months in a community adult sample of N = 862.
What This Means
This research suggests that poor sleep is largely a stable, trait-like characteristic in people — meaning that how someone sleeps tends to stay relatively consistent over time rather than fluctuating dramatically from month to month. Across a community sample of 862 adults followed over five months, about 83% of the variation in sleep disturbance reflected this stable, person-level trait rather than temporary state changes. People who chronically sleep poorly also tended to report higher levels of psychological distress (such as anxiety or depression) on average, with a moderate correlation between these two stable tendencies.
However, the research also found that short-term, month-to-month ups and downs in a person's sleep did not reliably predict subsequent changes in their psychological distress, and vice versa. Instead, when sleep disturbance and psychological distress fluctuated together within individuals, this tended to happen at the same time rather than one leading the other. Notably, this same-time (concurrent) link between sleep and distress within individuals grew slightly stronger over the course of the five months.
These findings matter because they suggest that the well-known connection between poor sleep and psychological distress may be largely driven by stable individual differences — some people are simply more prone to both — rather than short-term changes in sleep directly causing changes in mood or distress within the same person on a monthly basis. This research suggests that treatments targeting long-standing sleep problems may be important for addressing psychological distress, and that future research should examine whether shorter timescales (such as daily fluctuations) better capture within-person sleep-distress dynamics.
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Olatunji B, Knowles K, Cox R, Liu Q. (2026). The longitudinal structure of sleep disturbance: Time-varying and time-invariant components and associations with psychological distress.. Behaviour research and therapy. https://doi.org/10.1016/j.brat.2026.105038