Prolonged depression leads to brain inflammation

Depression that remains untreated for long periods, leads to brain inflammation, new research published in the Lancet Psychiatry has shown.

Researchers examined 25 patients who had suffered more than 10 years of depression, 25 with less than 10 years of illness and 30 people without depression, as a control.

CONSEQUENCES

They used brain imaging to map brain changes following years of persistent depression and found that when depression remains untreated for periods lasting more than a decade, it leads to brain inflammation.

For the study, brain inflammation was measured using a positron emission tomography (PET) scan—an imaging test that shows what is happening in the body—to help with diagnosis.

“The brain’s immune cells, known as microglia, are involved in the organ’s normal inflammatory response to trauma or injury, but too much inflammation is associated with degenerative illnesses and depression.

“When microglia are activated, they make more translocator proteins (TSPO), a marker of inflammation that can be seen using PET imaging,” wrote the researchers.

RESEARCH

TSPO levels were about 30 per cent higher in different brain regions in patients with prolonged and untreated depression, compared to those with shorter periods of untreated depression.

The group with long-term depression also had higher TSPO levels than those who were not depressed.

The brain changes indicate that persistent depression is a progressive, rather than a static disease, and that prolonged depression may need different treatment regimens at different stages of the illness.

Lead author Jeff Meyer, observed that patients with major depressive disorder are treated using the same approach without considering how long they have been unwell.

Some people may have had a couple of depressive episodes over a few years, while others may have had persistent episodes over a decade with worsening symptoms that lead to difficulties in going to work or carrying out routine activities.

TREATMENT OPTIONS

The findings, therefore, suggest that treatment approaches and techniques should be adjusted as the disease progresses in order to better assist patients.

The research team is investigating treatment options for this later stage of illness, such as using medication targeting brain inflammation.

Options include redesigning medication currently used for inflammation in other illnesses to be used in tackling depression-related disorders.

The researchers also noted that in treatment studies, patients with serious, long-standing depression tend to be excluded, so there is a lack of evidence on how to treat this stage of illness, and this needs to be addressed.