Mood disorders are a category of mental health conditions that involve persistent or intense changes in emotional state. They include major depressive disorder, bipolar disorder, dysthymia, and other related conditions. People with mood disorders may experience prolonged periods of sadness, emptiness, irritability, or episodes of abnormally elevated mood and energy. These disorders can affect daily functioning, relationships, and overall quality of life, but with appropriate treatment—such as therapy, medication, or a combination—many individuals manage symptoms effectively.