A person's mental well-being is as important as a person's physical state. Mood disorders are the type of disorders which directly affect the mood of a person, making them deeply depressed, lonely or unusually happy in the span of few minutes. These disorders can be classified into cyclothymic disorder, bipolar disorder, dysthymic disorder, clinical depression, etc. This book attempts to understand the varied disorders that fall under the discipline of mood disorders and how such diseases affect in the daily life and cause physical problems in the lives of the patients. Most of the topics introduced in it cover new diagnostic and treatment techniques of mood disorders. This textbook will serve as a reference to a broad spectrum of readers.