概日機能と抑うつ症状の関係における先延ばしの調整的役割：時間と自制心の衝突

Depression is highly prevalent and increasingly linked to circadian functioning and self-regulation. Yet little is known about how specific behaviors, such as procrastination, interact with chronotype dimensions to influence vulnerability to depressive symptoms. This study examined whether procrastination moderates associations between multidimensional chronotype and depressive symptoms in a large adult sample (N = 3606, aged 20-60). Participants completed self-report measures of chronotype, depressive symptoms, procrastination, and conscientiousness. Chronotype was assessed across three dimensions: Morning Affect (MA), Eveningness (EV), and Distinctness (DI). Results showed that lower MA and higher DI - reflecting greater daily energy fluctuations - were strong predictors of depressive symptoms. Procrastination significantly moderated these relationships by increasing overall levels of depressive symptoms: the protective effect of MA weakened at higher levels of procrastination, and the positive association between DI and depressive symptoms was stronger among individuals high in procrastination. No moderation emerged for EV, suggesting that circadian stability may be more relevant to emotional well-being than evening preference per se. When procrastination was included, conscientiousness no longer predicted depressive symptoms, indicating that procrastination may account for the link between low conscientiousness and depression. These findings underscore the importance of self-regulatory behaviors in the circadian-depression relationship.