If severe depression persists for long duration of time then it can become chronic and results in mood swings. Mood swing is a condition caused due to severe depression where it becomes extremely difficult to predict a person’s behavior. For one moment of time a person may feel extremely happy and excited and in the other moment the person becomes sad suddenly. The person may start crying suddenly without any reason. One of the reasons leading to severe depression is sudden hormonal change in the body. Hormones are responsible for controlling the person’s mood and so any change in hormone indefinitely bring change in normal behavior of the person. Every year the people getting affected by mood swing are increasing in number and the major cause for this is severe depression. The periods of time during which mood swings occur are divided into episodes. During these episodes person feels irritated, undergoes lack of sleep for excessive sleep, thousands of thoughts race in their mind simultaneously, the person will lose interest in routine work, and person gets feeling of worthlessness and hopelessness. Early treatment of mood swings occurring in severe depression is important because these people also tend to develop suicidal tendencies.