McGill researchers identify potential biological markers for teen depression

Researchers at McGill University have identified nine molecules in the blood that could help detect depression in teenagers earlier and more objectively.

The clinical study, published in Biological Psychiatry Global Open Science, found the molecules — called microRNAs — were elevated in teens diagnosed with depression. The same molecules also helped predict how symptoms might evolve over time.

“Alarmingly, more and more adolescents are being diagnosed with depression, and when it starts early, the effects can be long-lasting and severe,” said senior author Cecilia Flores, James McGill Professor in McGill’s Department of Psychiatry. “Teens with depression are more likely to struggle with substance use, social isolation and experience symptoms that often don’t respond well to treatment.”

The study involved 62 adolescents, including 34 diagnosed with depression. Blood was collected through a simple finger prick, dried, and frozen — a method the researchers say is minimally invasive and scalable.

“Our findings pave the way for using dried blood spots as a practical tool in psychiatric research, allowing us to track early biological changes linked to mental health using a minimally invasive method,” said first author Alice Morgunova, a postdoctoral fellow at McGill.

The microRNAs identified have not been linked to adult depression, suggesting they may reflect biological processes specific to adolescence.

Currently, depression is typically diagnosed through self-reported symptoms, which researchers say can delay treatment if teens don’t recognize or disclose what they’re experiencing. The team hopes that blood-based screening tools could offer a more objective approach.

Researchers plan to validate their findings in larger groups and explore how the identified molecules interact with genetic and environmental risk factors.