Mood disorders are a set of psychological conditions affecting the mood of an individual. They fall under the groups of elevated mood disorders (mania or hypomania), depressive disorders and moods that cycle between mania and depression. Cyclothymic disorder, dysthymic disorder and major depression are some of the common depressive disorders. Depressive disorders can be of different types, such as atypical depression, psychotic major depression, melancholic depression, catatonic depression, seasonal affective disorder and premenstrual dysphoric disorder, besides others. A mood disorder may be induced by a substance such as alcohol, benzodiazepine, etc. Several medical conditions such as, endocrine diseases, neurological disorders, gastrointestinal diseases, cancer, pulmonary disease, etc. can also trigger mood disorders. This book is a valuable compilation of topics, ranging from the basic to the most complex advancements in the understanding of mood disorders. It presents this complex medical condition in the most comprehensible language. For someone with an interest and eye for detail, this book covers the most significant aspects of such disorders.