Erectile dysfunction (ED) is the inability of a man to achieve or maintain an erection sufficient for his sexual needs or the needs of his partner. Most men experience this at some point in their lives, usually by age 40, and are not psychologically affected by it. Some men, however, experience chronic, complete erectile dysfunction (impotence), and others may experience partial or brief erections. Frequent erectile dysfunction can cause emotional and relationship problems, and often leads to diminished self-esteem. Erectile dysfunction has\ many causes, most of which are treatable, and is not an inevitable consequence of aging. Some common treatments include lifestyle changes, medication and specialist care.