Final answer:
Mood disorders are characterized by significant changes in mood that cause distress and impair functioning, with depression and bipolar disorder being the two main types.
Step-by-step explanation:
Mood Disorders Characterization and Types
Mood disorders are characterized by significant alterations in an individual's mood that cause distress and impair daily functioning. Unlike personality disorders, which are enduring and inflexible patterns of behavior, mood disorders involve substantial changes in emotional state. The two most common types of mood disorders are depression (including major depressive disorder and dysthymic disorder) and bipolar disorder. Depression is characterized by a severely depressed mood lasting longer than two weeks, among other symptoms. Bipolar disorder, formerly known as manic depression, involves dramatic shifts in mood and energy levels, which can affect an individual's ability to carry out day-to-day tasks.