While people often experience anxiety and depression together, psychiatrists classify them as different disorders. And now, there is biochemical evidence for this.
In a study, researchers from the Netherlands Study of Anxiety and Depression collected blood samples from 304 people with depression, 548 people with anxiety, 531 people with both conditions, 807 with remitted disorders, and 634 healthy individuals.
They then searched for links between 40 metabolites found in the blood and symptoms of depression and anxiety with a nuclear magnetic resonance detector.
In the end, the researchers made two major discoveries. The first was that those with depression tended to have greater inflammation than those with anxiety.
They also found that those with depression and anxiety have very different levels and types of lipids in their blood. While depressed people had higher levels of triglycerides and lower levels of omega-3 fatty acids, those with anxiety had lipid levels similar to those in the healthy group. The researchers also noted that depression severity tended to correlate with the presence of depression-associated metabolites.
Ultimately, they hope that their findings will go on to inform new treatments for depression and anxiety. To this end, they are now planning to test whether anti-inflammatory drugs are effective in treating people with depression.
“This is an important finding for several reasons. First, it identifies easy-to-measure blood biomarkers characterizing a subtype of depression whose underlying mechanism is specific and will probably need an appropriate treatment. “ says Dr. Philippe Nuss from l’Hopital Saint-Antoine, Paris.
“It also emphasizes the fact that mental disorders should be seen in a whole-body perspective where major regulatory physiological systems such as immunity and lipid metabolism are involved. In addition, both immunity and lipids are strongly involved in brain metabolism.”