What is a primary characteristic of Bipolar Disorder?

A primary characteristic of Bipolar Disorder is the presence of extreme mood swings, which include one or more manic episodes. During a manic episode, individuals may experience elevated or irritable mood, increased energy, decreased need for sleep, and often engage in risky behaviors. These mood swings can drastically affect a person's functioning and overall quality of life, as they oscillate between the manic phase and depressive episodes.

In contrast, the other options highlight symptoms that are more characteristic of different mental health disorders. Hallucinations and delusions are typically associated with schizophrenia or severe psychotic disorders. Social withdrawal and lack of speech could indicate depression or social anxiety but are not defining traits of bipolar disorder. Lastly, confused speech patterns and poor hygiene are symptoms that may arise in various conditions but do not specifically denote bipolar disorder. Therefore, the correct choice emphasizes the hallmark of mood fluctuations central to the diagnosis of bipolar disorder.