Shorter Sleep Duration Associated with Poor Executive Functions in Adolescents, Not Insomnia Symptoms

Author(s):

A sleep study on adolescents and their insomnia symptoms showed that those with a shorter sleep duration experienced deficient executive functions in daily life.

Reut Gruber, PhD

A recent study of 100 adolescents with no medical or psychiatric comorbidity demonstrated that having a shorter sleep duration was associated with poorer executive functions (EFs), otherwise behavioral competencies and cognitive skills that are important for daily functioning.¹This study’s findings provided factual data on daytime impairments associated with insomnia symptoms in this age group that may motivate the establishment of interventions to combat this problem in the future.

Shorter sleep duration was associated with a higher score on the Global Executive Composite Score (ΔR2 = 0.16, P <.001), the Metacognition Index (ΔR2 = 0.15, P <.001), and the Behavioral Regulation Index (ΔR2 = 0.11, P <.001).¹Notably, the Insomnia Severity Index did not contribute significantly to the explained variance in Global Executive Composite Score (ΔR2 = 0.01, P >.05), the Metacognition Index (ΔR2 = 0.02, P >.05), and the Behavioral Regulation Index (ΔR2 = 0.005, P >.05).

Lead investigator Reut Gruber, PhD, director, attention, behavior and sleep laboratory, Douglas Research Center, and colleagues wrote that the “findings suggest that adolescence may be a critical developmental period for interventions aimed at protecting executive functions in adolescents with objective short sleep duration.”¹ Before conducting the study, the investigators hypothesized a relationship between higher insomnia severity and shorter sleep duration and the outcome leading to be poorer EFs in the daily life of adolescents.

There were 61 girls and 39 boys adolescents with no medical or psychiatric comorbidity that participated in the study (mean age = 13.17; SD = 1.12). The study included participants with no clinically significant insomnia (n = 51), those with subthreshold insomnia (n = 39), and participants with clinical insomnia (n = 10). In terms of demographics, most were Caucasian (84.6% %), whereas the rest identified as either mixed ethnicity (8.9%), Asian (5%), or Hispanic (1.5%). As for household incomes, 5.15% of the participants had an annual combined income less than $45,000, 14.43% had annual incomes of $45,000–$65,000, 16.49% had annual incomes of $65,000–$95,000, and 63.92% had annual incomes greater than $95,000.¹

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The participants that were eligible for the study were given a wearable actigraph device and were told to wear it at bedtime for 6 consecutive nights on their nondominant wrist. During the 6 nights, participants were also asked to complete a sleep log daily and fill out the Insomnia Severity Index. The parents were asked about their adolescent's demographic and health information and to fill out the Behavior Rating Inventory of Executive Function (BRIEF). Overall, the measures included in the study were insomnia severity, sleep duration, and EFs.

Gruber who also serves as apsychologist atDouglas Mental Health University Institute, and colleagues noted, “The objectively measured sleep duration accounted for 16%, 15%, and 11% of the of the variance on the BRIEF Global Executive Composite, Metacognition Index, and Behavioral Regulation Index, respectively, after controlling for age, gender and circadian preference. Adolescents’ self-reported symptoms of insomnia did not add significantly to the explained variance of daily EFs beyond the impacts of sleep duration and the covariates.”¹

Prior studies on insomnia and short sleep duration with adolescents have shown an association with multiple cognitive, emotional and physiological impairments, which is consistent with the findings from the current study.² Other previous studies with insomnia and short sleep duration had hypothesized the association being linked because of biological roots whereas with self-reported insomnia was related to having a poor lifestyle.^3,4 A limitation to this study is that the design, cross sectional, does not permit the deduction of causal associations.

Gruberand colleagues noted, “Studies seeking to detect associations between sleep and daytime impairments or improvements in adolescents with insomnia would benefit from using objective sleep measures in addition to adolescents’ self-reported insomnia symptoms.”¹

REFERENCES
1. Gruber R, Sommerville G, Panaitescu A, Saha S. Sleep duration, but not insomnia symptoms, is associated with poor executive functions in adolescents. Sleep Med. 2022;101:36-39. doi:10.1016/j.sleep.2022.10.009
2. Vgontzas AN, Fernandez-Mendoza J, Liao D, Bixler EO. Insomnia with objective short sleep duration: the most biologically severe phenotype of the disorder. Sleep Med Rev. 2013;17(4):241-254. doi:10.1016/j.smrv.2012.09.005
3. Fernandez-Mendoza J, Baker JH, Vgontzas AN, Gaines J, Liao D, Bixler EO. Insomnia symptoms with objective short sleep duration are associated with systemic inflammation in adolescents. Brain Behav Immun. 2017;61:110-116. doi:10.1016/j.bbi.2016.12.026
4. Fernandez-Mendoza J, Calhoun SL, Vgontzas AN, et al. Insomnia Phenotypes Based on Objective Sleep Duration in Adolescents: Depression Risk and Differential Behavioral Profiles. Brain Sci. 2016;6(4):59. Published 2016 Dec 13. doi:10.3390/brainsci6040059