Study finds body clock type of depression in about one in four
About one in four people with severe depression in an Australian study had a type linked to the body clock, the Guardian and ABC News reported. They may respond less well to common antidepressants. Outside experts said more research is needed before doctors use the label.
Nearly a quarter of people with severe depression in a big Australian study had a type tied to the body clock, according to the Guardian and ABC News. Researchers call it "circadian depression." The study was published in The British Journal of Psychiatry.
The team looked at health and gene data from 11,380 Australians with serious depression, the Guardian and ABC reported. About 23% met the criteria, the Guardian said. ABC put the number at 2,604 people.
People were counted if they had at least three of six traits, the outlets reported. These include a seasonal pattern, going to bed late, sleeping more when depressed, being a night owl and waking up very tired.
People with this type had worse symptoms, said lead author Emiliana Tonini of the University of Sydney, according to the Guardian. Their depression started younger, and they had more episodes, she said.
The group also had higher genetic risk for ADHD, the Guardian and ABC reported. "This is important because that indicates that circadian depression is not just depression with bad sleep," Tonini said, according to the Guardian.
Common antidepressants worked less well and caused more side effects in this group, the study found, the Guardian reported. But Tonini said that finding came from what patients reported themselves, so it needs more testing, ABC reported. Treatments such as light therapy and melatonin may help, the researchers said.
The study only included people of European ancestry, the Guardian reported. The authors wrote that "future studies are needed to replicate our findings in diverse samples," according to the Guardian.
Philip Mitchell, a professor at the University of New South Wales, was not part of the study. He said the idea is "not reaching the bar where this could enter clinical practice," ABC reported. Jayashri Kulkarni of Monash University, also not involved, called it a "really well-conducted study," the Guardian reported.
What we know: About one in four people in the study fit a proposed body clock type of depression.
What we don't: Whether other studies will confirm it and whether targeted treatments work better.
Where outlets agree The Guardian and ABC News report that an Australian study of 11,380 people with severe depression found that about a quarter fit a proposed circadian subtype linked to the body clock.
Where they differ The Guardian puts the circadian subtype at nearly a quarter, or 23%, of participants, while ABC News describes it as about one in four.