Doctor Being down in the mouth is one thing, depression quite another. Aside from the emotional symptoms, it can cause fatigue, inability to sleep or concentrate, loss of interest in pleasurable activities and lack of desire to eat. And, although researchers have discovered some risk factors for depression – seasonal affective disorder and certain medications, for example, many aspects of it remain a mystery.
Now, though, new research from AstraZeneca Pharmaceuticals indicates that one way in which depression can occur is via the immune system. At least, that is what studies on mice show. Researchers found that when the mice had heightened immune response – as a person would if they were fighting an illness or stress – they were likely to run less on wheels in their cages. Wheel-running is an activity mice usually actively choose to do. When the researchers blocked the immune hormone which carries sickness signals to the brain, the mice resumed their usual activities.
The researchers had noted that people often become depressed when their body is going through an immune response to illness or stress, and also that in some depressed patients high levels of immune hormones have been discovered – even when the patient is otherwise healthy. This led the researchers to theorise that immune hormones somehow have a role to play in depression, and while this study was only on mice, it at least paves the way to further study on humans.
First published November 18, 2010