Bipolar disorder is a brain disorder characterized by unusual shifts in mood and ability to function. It is classified by the current mood state which can include mania, hypomania, mild or moderate depression, or severe depression, with or without psychotic features. The causes are thought to include neurochemical imbalances, genetic factors, and sleep disturbances. Symptoms include changes in appetite, energy, thoughts, and behavior. Treatment involves pharmacological interventions like mood stabilizers, antipsychotics, and antidepressants as well as non-pharmacological therapies like cognitive behavioral therapy and family therapy. Nursing care focuses on safety, monitoring for symptoms, providing education, and supporting treatment adherence.