Affective temperaments moderate the effect of insomnia on depressive symptoms in adult community volunteers.

Background: Insomnia and affective temperaments influence depressive symptoms in the general population. However, the ways in which the interaction between insomnia and affective temperaments affects depressive symptoms remains unknown. We studied the moderating effects of affective temperaments on the relationship between insomnia and depressive symptoms in adult community volunteers.

Methods: The participants were recruited from a community in Japan (n = 525). The Athens Insomnia Scale; Temperament Evaluation of Memphis, Pisa, Paris, and San Diego Auto-questionnaire version; and Patient Health Questionnaire-9 were used to evaluate insomnia, affective temperaments, and depressive symptoms, respectively. A hierarchical multiple regression analysis were conducted to evaluate the interactions.

Results: Insomnia significantly and positively interacted with cyclothymic, depressive, and anxious temperaments with regard to depressive symptoms, while insomnia significantly and negatively interacted with hyperthymic temperament on depressive symptoms. No significant interaction between insomnia and irritable temperament with regard to depressive symptoms were observed.

Limitations: Since the participants were adult community volunteers in Japan, the results may not be generalizable to other communities.

Conclusions: This study suggests that the influence of insomnia on depressive symptoms is moderated positively by cyclothymic, depressive, and anxious temperament and negatively by hyperthymic temperament. In adult community volunteers, affective temperaments may moderate the influence that insomnia has on depressive symptoms. Therefore, it may be useful to consider affective temperaments while dealing with depressive symptoms associated with insomnia.