Bipolar disorder is a debilitating mental illness which is characterized by alternating, episodic periods of mania and depression. This illness, and its unusual shifting of moods, can disrupt an individuals everyday functioning and thought processes, leading to disrupted behaviours, sleep patterns, and levels of activity. Researchers are currently working with medical imaging to gain a better understanding of how the structure of the brain may be contributing to the disease. One method of visualizing the brain is known as diffusion MRI. This technique uses the movement of water to create images that allow us to understand how the different parts of the brain are structured. Different areas of the brain are connected by tracts which are known as white matter tracts. It has been proposed that bipolar disorder is associated with disorganization in the architecture of these tracts, disrupting the communication between structures of the brain. The image produced by diffusion MRI is like picture made of individual pixels, called voxels. These voxels will be analysed individually to look at the organization and direction of nerve fiber bundles, and to look at the free water surrounding these fibers. Using this approach not only can an understanding of the tract abnormalities be obtained, but can be differentiated from changes in the surrounding free water. Should free water be similar in patient and comparison participant groups, this research will progress our understanding of white matter degeneration in bipolar disorder, and refine the tracts affected by degeneration.