Understanding immuno-metabolic depression
Researchers from ImmunoMIND recently published a review of the research about a form of depression called immuno-metabolic depression.
Depression affects over 38 million Europeans per year, with more people being diagnosed every year. Because depression varies so much from person to person, finding the right treatment can be challenging.
Understanding the biological factors behind depression and its different forms could help create more personalised treatments.
What is immuno-metabolic depression?
Many people with depression experience energy-related symptoms, such as excessive sleepiness, fatigue, increased appetite, and a lack of pleasure in activities.
However, research has shown about 20–30% of people with depression also have higher levels of certain immune markers in their blood, like C-reactive protein and cytokines. This indicates their body is experiencing long-lasting, low-level inflammation.
They also often experience metabolic problems, such as obesity, high cholesterol, and resistance to insulin and leptin (hormones that regulate blood sugar and hunger).
People with immuno-metabolic depression are at a greater risk of developing heart disease and other metabolic disorders. They also tend to respond poorly to standard antidepressants.
What causes immuno-metabolic depression?
We know there is no one cause of depression, and more research is needed to fully understand how people develop immuno-metabolic depression specifically. From the data which the researchers at ImmunoMIND looked at, it seems to be a combination of genetics, environmental factors and lifestyle. They also noted that early life stress and trauma might play a role.
The researchers looked at studies tracking people over time, and these studies suggest that immune and metabolism problems can contribute to depression, and depression can also lead to these health issues. So, there is an ongoing cycle in which the conditions impact on each other over time.
What the researchers noted, is there are overlaps in the mechanisms for these conditions. So far, the data suggests that treatments focusing on inflammation, metabolism, or lifestyle changes might be helpful for people with immuno-metabolic depression. This supports the idea of treating people based on their unique needs, rather than using a one-size-fits-all approach in mental health care.
Why is this research important?
Major depressive disorder is a common and serious mental health condition that affects people in different ways. If research can unpick the biological causes of depression and its various types, it could lead to treatments that are better suited to each individual.
Brenda Penninx, lead author on the paper, told us:
Depression is a heterogeneous condition, where different patients can have different symptoms as well as underlying biological mechanisms. Recognizing that immune-metabolic mechanisms could be a relevant treatment target for part of the depressed population opens the doors to personalised psychiatry.
What’s next?
The researchers say we need more research into immuno-metabolic depression before the findings can be used to help people with depression.
First, we need to better understand how biological and environmental factors work together to link immune and metabolic issues with depression symptoms. This connection is complex, and we don’t yet know all the details.
Second, we need to understand whether changes in the immune and metabolic systems directly cause depression, or if they just happen to appear alongside depression without actually driving it.
Third, we need more studies looking at treatments for depression which target the immune system and metabolism. Many studies are small and focus on different biological markers, making it hard to compare results. More collaboration is needed across studies to figure out which treatments work best and for which people, based on their unique symptoms and biology.
At the MHP, we are bringing together researchers from across disciplines, helping them work together with common goals and shared resources, so we can make progress faster.
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