Why being depressed can make your brain shrink!

For many sufferers, depression brings on many kinds of emotions and feelings including anxiety, guilt and shame, so it’s not surprising that many people fail to seek help. Often, many of the feelings that are associated with depression are, in part, caused by a general lack of understanding of the condition, not only by the sufferer, but by family members, friends, employers and colleagues. And yet the majority of people will experience some psychological problems during their lives. In fact very few people will go through life without experiencing some form of mental trauma of some description. But what is it that goes on in your head when you are feeling depressed?

There is increasing scientific focus on the mechanisms that occur within the body and brain of depressed patients. Indeed, it is becoming much clearer that inflammation significantly contributes to the cause and progress of depression, and that this triggers a myriad of processes that all contribute to the symptoms associated with the condition. It is difficult to comprehend that inflammation can trigger depression, because it is generally thought of as a response to injury or irritation that is characterised by physical processes such as pain and swelling.

However, inflammation need not be physical or obvious, and inflammatory processes and brain-immune interactions are now known to be involved in the development of major depression. Inflammation is certainly suggested to contribute to the dysfunction of biological systems involved in the production of important neurotransmitters (brain hormones) such as serotonin and noradrenalin. Indeed, increased levels of inflammatory products called cytokines (produced by immune cells, and involved in relaying messages between cells) have consistently been reported in patients with depression. Pro-inflammatory cytokines have many physiological functions but, significantly, have been reported to modulate central nervous system functions including a process called neurogenesis, which is simply the method by which nerve cells are generated. Excessive inflammation, and the production of cytokines amongst other things, causes a series of processes that ultimately damage neurones leading to their death. When cells within the brain die, this causes atrophy, or shrinking, by which there is loss of brain gray matter. Structural brain changes detected by a process called MRI scanning in depressed patients have been reported in several brain regions.

However, there appears to be hope offered through supplementing with fish oil. EPA is an omega-3 fatty acid known to help the symptoms of depression and reduce levels of inflammatory cytokines, whilst producing beneficial anti-inflammatory products. There is increasing scientific interest in the ability of EPA to prevent neuronal cell death and therefore reduce or prevent gray matter loss. Much of the pioneering work has focused on the role of EPA in Huntington’s disease with extremely promising results. Given the evidence that omega-3 fatty acids are beneficial for conditions in which there is reduced gray matter atrophy, such as Huntington’s disease, supplementing with ethyl-EPA may have further positive benefits on gray matter volume in individuals with depression, and further studies to support this hypothesis are certainly warranted.

Puri BK, Bydder GM, Manku MS, Clarke A, Waldman AD, Beckmann CF. (2008)
Reduction in cerebral atrophy associated with ethyl-eicosapentaenoic acid treatment in patients with Huntington’s disease. J Int Med Res. 36: 896-905.

Song C, Wang H. Cytokines mediated inflammation and decreased neurogenesis in animal models of depression.Prog Neuropsychopharmacol Biol Psychiatry. 2010 [Epub ahead of print]