‘Circadian Depression’ May Overlap With Seasonal Depression, but Researchers Say It’s Not Identical
Seasonal affective disorder (SAD), a type of depression that waxes and wanes with annual weather patterns, seems to involve circadian rhythm disturbances, too, but it’s a much narrower concept, says Dr. Tonini.
Seasonal mood changes are only one of the six markers of circadian depression. In the study, about 41 percent of people with circadian depression had them.
People with circadian depression were also more likely to report a bipolar disorder diagnosis and to meet criteria for atypical depression, a type marked in part by sleeping too much and weight gain, says Kruse.
“Rather than completely separate kinds of depression, these features are likely distinct but overlapping dimensions of the illness,” she says.
Light Therapy May Help Depression, but Evidence for Melatonin Is Limited
The study didn’t test light therapy or melatonin,
