Brain scan study identifies potential target for treating severely depressed young people | Depression

Young people with severe depression experience disruptions to the way areas of the brain communicate with each other. What is seen in adultsThis was revealed through research.

The study published Tuesday Nature Mental Health It can be used to identify potential targets for brain stimulation therapy, expanding existing applications beyond adults to adolescents.

The study analysed brain scans from 810 young people aged 12 to 25 years, of whom 440 had major depressive disorder (MDD) and 370 were healthy comparison subjects.

A University of Melbourne-led study found that people with MDD had stronger connectivity in some of the brain's densely connected regions (called hubs), and weaker connectivity in others, compared with young people without depression.

Lead researcher Professor Andrew Zaleski said the connections were particularly strong in parts of the brain associated with internalised thinking and rumination. “In young people with depression, the default mode was more connected and more active, suggesting there was more of an emphasis on self-thinking and self-reflection,” he said.

The study, lead authored by Ngga (Connie) Yang Tse, a third-year PhD student at the University of Melbourne, also found that the extent of these differences could reliably predict the severity of a person's depressive symptoms.

The researchers used data from previous, independent studies conducted in six locations: Australia, China, the UK and the US to achieve what Zaleski calls “the largest sample size ever to compare depressed and healthy young people.”

Brain stimulation therapy aims to repair specific brain circuits as an alternative approach to treating depression. First-line treatmentZaleski said medications such as antidepressants can also help.

But now that researchers know which circuits are disrupted, it is becoming more commonly administered as a treatment for adults.

Targets developed to treat depression in adults with transcranial magnetic stimulation (TMS) have also been used to treat young people as a “best guess approach,” according to the paper.

Australia's medicines regulator, the Therapeutic Goods Administration, recommends TMS only for adults, but it can be offered to young people at a doctor's discretion, Zaleski said.

“It was assumed that the same circuits would be affected in depressed youth, but our study shows that this is not necessarily the case.

“While there is some overlap with connectivity disorders seen in adults, there are also unique and specific circuit impairments that are seen only in depressed youth.”

For example, researchers have found that networks that help identify the most relevant information at any given time are widely implicated in adolescent MDD but have mixed results in adult depression, Zaleski said.

More studies need to be done to test the effectiveness and safety of brain stimulation in young people before it can be implemented more widely by clinicians, but “this is a necessary first step to provide a goal,” Zaleski said.

Dr Holly Byrne, a postdoctoral research fellow at the Matilda Psychiatric Research Centre, health Professor of psychiatry and substance use at the University of Sydney, who was not involved in the study, said that while the research provides “important evidence for identifying potential therapeutic targets” for brain stimulation therapy, “it is important to remember that there is no 'one size fits all' approach to treating depression.”

“Neuromodulation therapy is now recommended in conjunction with other treatment options as part of a comprehensive, individualized treatment plan or when other treatment options have been exhausted,” Byrne said.

“The work described in this study extends the findings in adults with MDD to adolescent/young adult depression,” said Dr Stevan Nicolin, a neuroscience research fellow at the Black Dog Institute.

“This study improves our understanding of the disorder in young people, and this understanding may allow future interventions to be designed to specifically address the pathological brain activity identified,” Nicolin said.

The authors also acknowledge that the study has limitations, including only examining each depressed young person at one point in time.

Zaleski acknowledged that without further clinical trials, any inferences about brain stimulation should still be taken with caution.