Association between grit and insomnia: A population-based study

Background: This study aimed to investigate the association of the grit scale, a personality trait characterized by perseverance and passion, with both the presence and the severity of insomnia in the Korean adult population.

Methods: A nationwide population-based cross-sectional survey was conducted through face-to-face interviews using structured questionnaires between September and December 2018 in Korea. Grit was assessed by using the 8-item Short Grit Scale. Participants were categorized into insomnia and non-insomnia groups based on a threshold of 10 on the Insomnia Severity Index (ISI). The association between girt and insomnia was analyzed using multiple linear regression and multivariable logistic regression, controlling for sociodemographic factors, lifestyles, and comorbidities.

Results: A total of 2453 participants (49.9 % male; aged 19-92 years) were enrolled in the study. Individual grit scores ranged from 1.75 to 5.00 points (mean [SD], 3.27 [0.42]), and insomnia was present in 16.5 % of the population. The insomnia group exhibited lower grit score compared to the non-insomnia group (3.11 [0.40] vs. 3.30 [0.42], p < 0.001, Cohen's d = 0.46). Grit was negatively associated with ISI scores (β = -0.15, 95 % CI = -0.19, -0.11, p < 0.001) and with having insomnia (OR 0.40, 95 % CI = 0.30, 0.55, p < 0.001), after controlling for covariates.

Conclusions: Individuals with higher grit were less likely to have insomnia. Clinicians should consider personality traits, such as grit, in the evaluation and the management of insomnia.