Intraindividual Variability Not Associated With Problematic Alcohol Use

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The results show intraindividual variability in total sleep time, time in bed, midpoint sleep, bedtime, and risetime were associated with lower sleep quality.

New research indicates greater fluctuations in sleep time, time spent in bed, and risetime are negatively associated with an individual’s overall sleep quality.1

A team, led by Misol Kwon, University at Buffalo School of Nursing, examined the objective intraindividual variability (IIV) in sleep and its relationship to sleep and mental health outcomes among adolescent patients with a history of alcohol use.

Assessing Sleep

In recent years, several studies have focused on the ecological momentary assessment by uses of sleep diary and actigraphy. However, there is a need to focus on the relationship between fluctuations that exist in sleep measures on adolescent health outcomes, where above the impact of mean sleep measures, intraindividual variability (IIV) in sleep are helpful to determine the degree of which daily variations or fluctuations in sleep/wake patterns are occurring.

This could also prompt important cures for adolescent health outcomes.

In the study, presented during SLEEP 2023 in Indianapolis,the investigators analyzed 8 days of wrist actigraphy data involving 72 high school students who reported prior alcohol use. The patient population was 58.3% female with a mean age of 17 years.

The investigators calculated IIV in total sleep time (TST),time in bed (TIB), midpoint sleep, bedtime, and risetime, using Bayesian variability methods.

Each participant completed the Pittsburgh Sleep Quality Index (PSQI), Cleveland Adolescent Sleepiness Questionnaire (CASQ), Inventory of Depressive Symptomatology (IDS-SR-30), Chapman’s Inventories – Social Anhedonia (CHAPSAS), and Rutgers Alcohol Problem Index (RAPI).

The team adjusted for biological sex, age, and the sum of alcohol drinks in the previous 3 months using multiple linear regression models.

Alcohol Consumed

Each participant reported an average of 18.52 total drinks consumed over the previous 3 months.

The results show IIV in TST, TIB, and risetime were linked to lower sleep quality (B = 3.04; 95% confidence interval [CI], 0.02-7.39; P <0.05 for IIV in TST; B = 2.87; 95% CI, 0.39-5.88; P <0.05 for IIV in TIB; B = 2.74; 95% CI, 0.57-6.19; P <0.05 for IIV in risetime).

However, they did not observe a statistically significant association between IIV of sleep measures and excessive daytime sleepiness or mental health outcomes, including social anhedonia, depressive symptoms, and problematic alcohol use.

“Greater fluctuation in TST, TIB, and risetime were negatively associated with overall sleep quality,” the authors wrote. “Our findings add to a growing body of research on IIV in sleep/wake patterns and clinical implications. Future studies should explore the prospective relationship between variability in sleep and other various health outcomes.”


Misol Kwon and others, 0102 Are there associations between intraindividual variability in sleep and mental health among adolescents reporting alcohol use?, Sleep, Volume 46, Issue Supplement_1, May 2023, Page A46,