Migraine is a symptomatically heterogeneous condition, of which
headache is just one manifestation.
Migraine is a disorder of altered sensory thresholding, with
hypersensitivity among sufferers to sensory input. Advances in functional neuroimaging have highlighted that several brain areas are involved even prior to
pain onset. Clinically, patients can experience symptoms hours to days prior to
migraine pain, which can warn of impending
headache. These symptoms can include mood and cognitive change,
fatigue, and neck discomfort. Some epidemiological studies have suggested that
migraine is associated in a bidirectional fashion with other disorders, such as
mood disorders and chronic
fatigue, as well as with other
pain conditions such as
fibromyalgia. This review will focus on the literature surrounding alterations in
fatigue, mood, and cognition in particular, in association with
migraine, and the suggested links to disorders such as
chronic fatigue syndrome and depression. We hypothesize that
migraine should be considered a neural disorder of brain function, in which alterations in aminergic networks integrating the limbic system with the sensory and homeostatic systems occur early and persist after
headache resolution and perhaps interictally. The associations with some of these other disorders may allude to the inherent sensory sensitivity of the
migraine brain and shared neurobiology and
neurotransmitter systems rather than true co-morbidity.