Elation refers to the positive mental reaction when the ego's hope of eventually being happy seems imminent or likely. It is future oriented. It can boost energy in the present and provide a 'heady' type of positive feeling. The opposite idea is dejection which is a negative evaluation of future prospects of being happy. Elation and dejection are different from emotions. Emotions are based in the body, not in the ego, and emotions are in the present. To the extent that a person is estranged from the body and from emotion, elation (and dejection) will assume huge importance. However, elation, while it can bring about some excitement, cannot bring about satisfaction. That is why elation can act as a mirage--seemingly offering the prospect of pleasure but never really delivering it.
All depression is to some extent 'bipolar', that is, it stems from the flooding in of dejection when an illusion is burst and resolves, (usually), when an illusion (perhaps the same basic illusion) is rebuilt around another idea. The way out of the cycle of depression is usually thought to be overcoming dejection, but it is really about overcoming elation and the false promise of joy that elation provides.