Grant: China-Canada Joint Health Research Initiative

Major depressive disorder affects 10% of the world's population and is one of the leading causes of disability worldwide. Research suggests that the brain, genetics, and environmental factors contribute to depression. Although the cause of major depression is unknown, it is accepted that there is a network problem in the brain as opposed to a problem in a single neurotransmitter or brain region. Research suggests that white matter damage in the brain may be a critical factor. White matter is composed of cells in the brain that have a protective coating around them called myelin. Myelin insulates the brain cells much like the coating on a wire and allows cells to send electrical messages to each other rapidly and efficiently, forming the basis of movement, thought, and behaviour. Abnormalities in myelin results in communication disruptions and deficits follow. Our research team has designed a project that will span human clinical studies, animal models of depression, and cell biology to examine the role myelin in depression and the effect of antidepressant treatment on myelin. The human studies will examine if there are specific genes associated with depression. MRI's will be used to detect if myelin is damaged in patients with depression, if myelin abnormalities are related to gene alterations, and if antidepressants have an effect on myelin. The animal model of depression studies will tell us how myelin causes depression symptoms and how antidepressants can prevent myelin damage using cell biology methods. This project will greatly enhance our understanding of what causes major depression. It will tell us how myelin causes depression, and what can be done to interrupt or reduce these abnormalities and improve the symptoms of depression. This could lead to changes in the way antidepressants are used and guide the development of new drugs that target myelin more directly, all of which would lead to improvements in the lives of people suffering from depression.