Bipolar disease consists of periods of abnormally and persistently elevated, expansive or irritable moods. Symptoms include grandiosity, flight of ideas, and a decreased need for sleep. The pathophysiology of bipolar disorder remains elusive despite a lot of evidence regarding the genetic, pharmacologic, anatomic and physiologic nature of the symptoms and the disease.
Unfortunately, no unifying hypothesis exists. One commonly used model describes a type of electrophysiological "kindling" (which means to flare-up or bring into being). It is assumed that there is an increase in either pre- or post-synaptic activity that builds until the entire posterior cingulate is involved.
A patient suffering from bipolar I disorder is likely to present all the following symptoms EXCEPT:
Extra info: Patients with bipolar I disorder can have manic symptoms associated with elevated mood (euphoria), changes in cognition and perception (delusions of grandeur), and increases in activity and behaviour (pressured speech). It is unlikely the patient will have hypersomnia since these patients typically report a decreased need for sleep.
The kindling theory of bipolar disorder can be summarized as:
Extra info: Episodes of mania occur in a pattern that is cyclical and with increasing frequency. Thus, this suggests that the pathophysiology is related to changes in the brain which predispose the patient to respond to various factors with a flare-up of symptoms. Since the episodes come with increasing frequency, it is assumed that the kindling becomes more sensitive.