McGill researchers identify blood markers linked to teen depression and brain changes

McGill researchers have identified nine blood molecules linked to depression in adolescents.

Researchers at McGill University have made a discovery that can help detect depression earlier in teens and predict how their symptoms may progress over time.

Dr. Cecilia Flores, a McGill James professor in the university’s Department of Psychiatry, said that depression is prevalent in adolescence, and very little is known about the causes.

She added that early intervention or prevention can have a major impact on the psychiatric trajectory of teens.

“We wanted to see if we could identify a marker in a very easy manner and measurable manner, and we looked for molecules that are known to mediate the interaction between the environment and biological processes, including those that occur in the brain,” Flores explained.

In layman’s terms, it’s how environmental factors such as stress, pollution or diet influence the body, especially the brain.

Using a novel lab method they developed, the researchers, including scientists from Stanford University and the University of California, Los Angeles, identified nine molecules in the blood that were elevated in adolescents diagnosed with depression.

“We managed to get the dry blood spots, which is like you get a little bit of blood from the finger, and you put it in a little piece of paper, and then with a lot of work we manage to get a lot of information about all these molecules,” Flores said.

The samples are left to dry and then frozen to preserve the molecular integrity over time. The new lab method is practical and scalable, making it well-suited for broader use.

“We also found that some of these molecules, their levels of expression in the blood, can predict the severity of depressive symptoms nine months later, but not of anxiety, suggesting that there is a specificity.”

The clinical study also revealed that the levels of these molecules correspond to changes in the volume of a brain region called the hippocampus, which is known to be associated with and play an important role in depression.

According to the researchers, these findings could ultimately pave the way for earlier detection – before symptoms worsen and become more difficult to treat.

The study focused on 62 teenagers in California: 34 with depression and 28 without.

McGill postdoctoral fellow and lead author of the study, Alice Morgunova, said that the lab method they developed has huge potential and makes it much easier to collect data from large groups of people.

“The critical part, of course, is to go beyond the current sample that we have studied. As we mentioned, specifically, this one is from California, so of course, it has a specific socio-demographic background, and it is critical for us to also expand this work,” Morgunova noted.

In fact, Morgunova said McGill researchers are currently recruiting youth to continue studying these molecules.

“So now that we have identified the candidates, we can use them to predict whether a different set of youth may be vulnerable to developing psychiatric disorder later on,” she said.

“And the critical aspect to this work is the fact that early onset of depression is associated with more severe symptoms, [which last] longer, and are resistant to treatment.”

Scientists are also taking a closer look at what these nine molecules do in the brain, how they affect brain development, and how they are involved in the biological process that leads to depression.

“And so far, what our paper is showing is that there is some association with these molecules with neurodevelopmental outcomes as well as how the brain develops. Therefore, it is critical for us to understand what the origins of the disorder may be,” Morgunova said.