A new study suggests that major depressive disorder may not be a single condition but two distinct biological forms, a finding that could help researchers develop more targeted treatments for patients.
Researchers found that people diagnosed with major depression can have different genetic profiles and physical health risks, despite receiving the same clinical diagnosis. The findings challenge the traditional view that major depression is a single illness.
Major depressive disorder is one of the world’s most common mental health conditions. It is marked by persistent sadness, loss of interest in daily activities, and can significantly affect quality of life.
To investigate why symptoms vary between patients, researchers analyzed genetic data from more than 460,000 people of European ancestry. They compared three symptom patterns, including people who experienced weight gain and excessive sleep, those with weight loss and insomnia, and a third group with mixed symptoms.
The study found clear biological differences between the first two groups.
People who gained weight and slept for longer periods were more likely to have a higher body mass index, type 2 diabetes, high blood pressure, heart disease, and increased levels of inflammation.
By contrast, those who experienced weight loss and insomnia showed different genetic characteristics and a lower risk of diabetes. Researchers also found a possible genetic link between this group and certain neurological conditions, including schizophrenia.
The research identified 27 genetic locations associated with major depression, including several that had not previously been linked to the disorder. Scientists said these discoveries could improve understanding of the condition’s underlying causes.
Researchers concluded that major depression likely includes different biological subtypes rather than a single disease. They believe future treatments could be tailored to each subtype, offering more personalized care instead of relying on a one-size-fits-all approach.
The team added that more research is needed to better understand how metabolic disorders are connected to depression and whether they contribute to its development or influence the severity of symptoms.
