Study Links Body Clock Disruptions to 23% of Depression Cases
Researchers have identified a ‘circadian depression’ subtype affecting nearly a quarter of patients, linked to disruptions in circadian rhythms.
A recent study has identified a new subtype of depression linked to disruptions in the body’s internal clock, termed ‘circadian depression’, affecting approximately 23% of participants.
The research, conducted by Australian scientists and published in the British Journal of Psychiatry, involved clinical and genetic data from 11,380 Australians with severe depression. The findings suggest that individuals with this subtype often respond poorly to traditional antidepressant treatments.
According to the study’s first author, Dr. Emiliana Tonini from the University of Sydney, circadian depression is characterized by symptoms such as seasonal mood changes, delayed sleep timing, and social jet lag. Those affected experience more severe symptoms and tend to exhibit complex depression trajectories, including increased suicidality and more frequent episodes.
“Individuals with circadian depression have more severe mental health symptoms,” Tonini stated.
Researchers found that participants with this subtype had a higher genetic risk for conditions such as ADHD and other mood disorders. Markers indicating metabolic and inflammatory issues were also present, highlighting the distinct biological underpinnings of this form of depression.
Professor Ian Hickie, co-director of the Brain and Mind Centre, emphasized the ineffectiveness of common treatments like selective serotonin reuptake inhibitors (SSRIs) for those with circadian depression, stating that these patients experience more side effects.
“What is critical about being in this circadian type is its poor response to the standard therapies,” Hickie said.
The researchers advocate for alternative treatments targeting circadian rhythms, including melatonin and light therapy, suggesting that clinicians should consider these options promptly for affected individuals. They believe that diagnosing circadian depression could lead to better treatment strategies, particularly for young patients.
Some experts urge caution. Professor Andrew Coogan, a behavioral neuroscientist, noted that while the findings are significant, their application in clinical settings requires further validation. He remarked on the need for more detailed criteria for diagnosing this new subtype.
The study also acknowledged limitations, indicating that the sample was predominantly of European ancestry, which may affect the generalizability of the results. Future research is expected to involve a wider variety of populations.
