Loneliness, laughter, and mental health in the Japanese general population: findings from a cross-sectional study.

Little is known about the link between laughter and loneliness in the general population. This is a significant omission given that both phenomena may be important for health. This study examined the loneliness-laughter association in Japanese adults and whether laughter is important for mental health in lonely individuals. Data were analyzed from 3,551 adults who participated in an online survey in 2023. Loneliness was assessed with the Three-Item Loneliness Scale, while a single question was used to obtain information on laughter status. The Patient Health Questionnaire-9 (PHQ-9) was used to obtain information on depression, while anxiety was assessed with the Generalized Anxiety Disorder-7 (GAD-7) scale. Logistic regression was utilized to examine associations. In an analysis that was adjusted for sociodemographic and mental health variables, loneliness was significantly associated with never/almost never laughing in the total sample (OR: 2.07, 95% CI: 1.64-2.61). In a sex-stratified analysis, loneliness was linked to never laughing in both men and women, although the association was stronger in women. Further analyses showed that compared to individuals who were not lonely and laughed (reference category), all combinations of the loneliness and laughter variables were associated with significantly higher odds of anxiety and depression in both men and women, with the highest odds observed in those who were lonely and never laughed. Loneliness is associated with never laughing among adults in Japan, with an absence of laughter being linked to higher odds of anxiety and depression in lonely individuals. These findings underscore the public health importance of reducing loneliness and promoting positive emotional experiences, such as laughter, to help mitigate the risk of anxiety and depression.