The pathogenesis of bipolar illness remains unknown, but alterations in ion regulation due to dysfunction in corresponding pumps and channels are highly reproducible ( El-Mallakh and Wyatt, 1995, Dubovsky and Franks, 1983 Shaw 1966 Coppen et al. In this light, animal models serve as tests of hypotheses, and inform the pathophysiology of the illness being studied. Doctor Joshua Gordon, the Director of the National Institute of Mental Health argues “ … we cannot claim that animals are models of diseases, but rather they are models for the study of disease.” ( Gordan, 2018). Bipolar II disorder is similar but involves an individual having at least one major depressive episode and at least one hypomanic episode (similar to mania but the symptoms are less severe and need only last a minimum of four days) ( American Psychiatric Association, 2013 El-Mallakh et al 2006).īecause so many of the symptoms are subjective (euphoria, grandiosity, depression, hopelessness, guilt, suicidality), or appear uniquely human (increased involvement in problematic behaviors, looseness or associations, rapid or slowed speech or thoughts) modeling bipolar illness in animals has been seen as problematic or impossible. Because depressive symptoms are also manifestations of unipolar major depressive disorder, bipolar I disorder is diagnosed on the basis of a manic episode ( American Psychiatric Association, 2013 El-Mallakh et al 2010). Between these periods of abnormal mood, the patients are euthymic, or experiencing normal moods.
During depressive episodes they may feel down, depressed, or extremely sad, along with hopeless, low energy, changes in sleep and appetite, poor concentration and slowed thinking, loss of interest and enjoyment, and thoughts of death or suicide ( American Psychiatric Association, 2013 El-Mallakh et al 2010). Additionally, they may display exaggerated self-esteem or grandiosity, increased risky behavior, decrease need for sleep, easily distracted, and uncontrolled racing thoughts ( American Psychiatric Association, 2013 El-Mallakh et al 2010). During manic episodes, which must last at least 7 days (unless a person is hospitalized), individuals may feel energetic, euphoric, or uncomfortably irritable. Type I bipolar I illness is generally viewed as the most severe of these and manifests with dramatic mood swings generally defined as mania and depression. It comprises three different conditions: bipolar I, bipolar II and cyclothymia. Bipolar disorder, or manic-depressive illness, is a psychiatric disorder that afflicts about 3 to 5 million people in United States ( Kessler et al.