Study shows that a protein found in the brain can cause symptoms of depression

A new study presented at the annual meeting of the Society for Neuroscience, shows that the immune system is involved in the development of depression.

Researchers found that the activation of the immune system caused mice to learn to run less, an activity they normally enjoy. After the action of interleukin-6 - a protein that acts as both a pro-inflammatory and anti-inflammatory cytokine which helps the immune system respond to trauma - was blocked, mice resumed the activity.

The study suggests that blocking the protein might reduce depression symptoms like fatigue and disinterest in activity that sufferers would normally like.

Furthermore, people who have never had a mental illness, but who are treated for other illnesses with immune-stimulating cytokines, have been shown to develop depression.

Researchers suggest that the study supports the notion that depression may be caused by a breakdown in the normal communication between the immune system and the brain, which can cause otherwise healthy people to show depressive symptoms.