This study aimed to investigate the association between sleep-related characteristics and depression among young Japanese women.
We distributed an online survey of young Japanese women ages 18 to 29 from November 8, 2022 to February 2, 2023, using Google Forms (Alphabet, Mountain View, CA, USA). The exclusion criteria were as follows: (a) current or past history of psychiatric and sleep disorders and (b) current use of tranquilizers and sleep-inducing medications. The Patient Health Questionnaire 2 (PHQ-2) was used to assess the frequency of depressed mood and anhedonia using a 4-point Likert scale (0-3). A score of 3 or more, out of 6, indicated positive depressive symptoms. The Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J) was used to examine sleep-related lifestyle habits. The PSQI-J can generate seven component scores (C1: subjective sleep quality; C2: sleep onset latency; C3: sleep duration; C4: habitual sleep efficiency; C5: sleep disturbance; C6: use of sleep medication; C7: daytime dysfunction) from a total of 18 items. The unpaired t-test and Mann-Whitney U test were used to compare sleep-related habits between the groups with and without depression. Multiple logistic analysis was conducted to identify factors influencing depression.
The survey was sent to 900 individuals, with 614 responses (response rate: 68.2%). After excluding 74, 540 were analyzed: 456 without depression and 84 with depression, based on PHQ-2 scores. The global PSQI-J score of the group with depression was 7.0 (5.0–9.0), significantly greater than 5.0 (3.0–7.0) of the group without depression. Significant differences were also observed in the PSQI-J subitems for subjective sleep quality, sleep onset latency, habitual sleep efficiency, sleep disturbance, use of sleeping medication, and daytime dysfunction (p0.001, p0.001, p=0.049, p=0.045, p=0.020, and p=0.020, respectively) between the two groups. Multiple logistic analysis revealed statistically significant associations between the presence of depression and sleep onset latency (β=0.299; p=0.031; OR, 1.348; 95% CI, 1.028–1.768) and daytime dysfunction (β=0.492; p0.001; OR, 1.635; 95% CI, 1.221–2.191).
Our findings indicate that depression may negatively impact sleep quality, as measured by the PSQI-J. Additionally, prolonged sleep onset latency and daytime dysfunction may serve as early indicators of depression. Thus, enhancing sleep quality can be crucial for protecting the mental health of young women in Japan, a country where sleep deprivation is prevalent.
The results will guide the development of appropriate interventions to prevent and treat sleep disorders and depression in young Japanese women.
Mental health
Young adults
