A group of mental disorders categorized by significant feelings of anxiety and fear are known as anxiety disorders. Anxiety is an emotion in which a person feels an unpleasant state of inner turmoil. Fear is a feeling caused by perceived danger or threat. These feelings can cause physical symptoms such as a fast heart rate and shakiness. The cause of anxiety disorders is a combination of environmental and genetic factors. It can also be caused due to drugs, stress and medical conditions. Anxiety disorders can be classified into generalized anxiety disorder, specific phobias, social anxiety disorder and panic disorder, etc. Depression is a condition of low mood and aversion to activity, which directly affects a person's thought, behavior, feelings, motivation, and sense of well-being. Depression can be long term as well as short term. It can cause sadness, difficulty in thinking and concentration, a feeling of dejection and hopelessness. Major depressive disorders are generally accompanied by anxiety disorders. This book provides comprehensive insights into anxiety disorder and depression. It is a compilation of chapters that discuss the most vital aspects related to this disorder. This book is a resource guide for experts as well as students.