New Depression Subtype Linked to Body Clock Disruption Identified
Researchers in Australia have identified a new subtype of depression, known as circadian depression, affecting nearly a quarter of patients with depression.
SYDNEY, Oct 24: A new subtype of depression, termed circadian depression, affects nearly 25% of individuals with depression, according to a study from researchers at the University of Sydney. This type is linked to disruptions in the body’s internal clock, leading to chronic feelings similar to jet lag without the need for travel.
The study examined data from 11,380 Australians, revealing that 2,604 participants showed symptoms fitting the criteria for circadian depression. These individuals reported more severe mental health issues, with an average onset age of 18.7 years, earlier than other depression types. Their experiences included excessive sleeping, pronounced morning exhaustion, and an overall preference for late-night hours.
Dr. Emiliana Tonini, first author of the study, stated, “Individuals with circadian depression have more severe mental health symptoms” and emphasized the need for better understanding of this subtype. The study found that people in this group have complex mental health trajectories, including higher suicidality and episodes resembling mania or psychosis.
Standard antidepressants, such as SSRIs and SNRIs, were reported to be less effective for those with this subtype, prompting researchers to suggest that treatments targeting circadian rhythms, such as melatonin and light therapy, may be more beneficial.
Co-author Ian Hickie noted, “Chronobiological treatments… focused on the sleep-wake cycle… is critical” for this group. The study’s findings emphasize that clinicians should consider an individual’s sleep timing when assessing treatment for depression.
Some experts are cautious about these findings. Ronan Lordan from the Royal College of Surgeons mentioned that the distinctions made in the study might not establish a clear biological subtype. He stressed the importance of examining sleep timing without prematurely categorizing patients. This sentiment is echoed by the director of the Monash Alfred Psychiatry Research Centre, who acknowledged the well-conducted nature of the study while pointing out the need to consider other factors, such as hormonal impacts during menopause.
The researchers acknowledge that their study participants predominantly came from a genetically inferred European ancestry, suggesting that further research is needed to validate these findings across diverse populations.
