“Phase Relationships between Core Body Temperature, Melatonin, and Sleep Are Associated With Depression Severity: Further Evidence for Circadian Misalignment in Non-Seasonal Depression”, 2010 (; backlinks; similar):
Misalignment between the timing of sleep and the circadian pacemaker has been linked to depression symptoms.
This study sought to extend earlier findings by comparing sleep and circadian markers in healthy controls and individuals with major depression.
Two markers of circadian misalignment correlated with depression severity in the depressed group.