Clinical meaning
Bipolar disorder is a chronic mood disorder characterized by cycling between episodes of mania (or hypomania) and depression, with euthymic (normal mood) periods between episodes. Bipolar I disorder requires at least one manic episode (elevated/expansive/irritable mood with increased energy lasting 7+ days or requiring hospitalization). Bipolar II disorder requires at least one hypomanic episode (4+ days, less severe than mania, no psychotic features, no hospitalization required) AND at least one major depressive episode. The pathophysiology involves dysregulation of multiple neurotransmitter systems: excessive dopamine activity during mania (explaining euphoria, grandiosity, psychomotor activation, and psychotic features), serotonin dysfunction (contributing to depressive episodes), and disrupted glutamate/GABA balance affecting neural excitability. Circadian rhythm disruption is central to bipolar disorder: the suprachiasmatic nucleus (biological clock) is dysregulated, causing sleep-wake cycle disturbances that can trigger mood episodes. Kindling theory suggests that initial episodes are triggered by external stressors, but over time, episodes become self-generating and more frequent without treatment, supporting the need for lifelong mood stabilizer therapy. The practical nurse monitors mood states, administers mood stabilizers, implements safety measures during acute episodes, and educates about medication...