Higher sleep reactivity and insomnia mutually aggravate depressive symptoms: a cross-sectional epidemiological study in Japan.

OBJECTIVE: Sleep reactivity assessed using the Ford Insomnia Response to Stress Test (FIRST) is associated with depression. This study clarified stress reactivity and insomnia effects on depressive symptoms.

METHODS: A cross-sectional questionnaire survey was administered to 2645 participating government employees (35.4% female, mean age 42.8 years) during health checks conducted at Tottori prefecture, Japan, in June 2012. Questionnaire items included: demographic information; the FIRST; the Pittsburgh Sleep Quality Index (PSQI); and a 12-item version of the Center for Epidemiological Studies Depression scale (CES-D). The study defined CES-D scores of ≥12 points as positive for depression, PSQI scores of ≥5.5 points as positive for insomnia symptoms, and FIRST scores of ≥19 points as indicating higher sleep reactivity.

RESULTS: Multivariate logistic regression analysis revealed insomnia (adjusted OR = 3.40), higher sleep reactivity (adjusted OR = 1.78), presence of disease currently being treated (adjusted OR = 1.84), and being female (adjusted OR = 1.53) as independently associated with depression. Participants with insomnia and a high FIRST score showed higher CES-D scores than those with insomnia alone and those with high FIRST without insomnia (all p < 0.01).

CONCLUSIONS: Sleep reactivity might be associated with depression, independent of insomnia. Elevated sleep reactivity and insomnia symptoms are thought to aggravate depressive symptoms.