Between 2 million and 30 million men in the United States are affected by impotence problems, according to recent estimates. About 52% of men aged 40 to 70 have some degree of erectile dysfunction (ED). Approximately 90% of cases of ED are caused by physical, not psychological, problems.

Risk factors for ED include the following:

• Hypertension (high blood pressure)
• Hyperlipidemia (high cholesterol)
• Endocrine disorders
  • low testosterone (such as patients receiving hormonal therapy for prostate cancer or patients with hypogonadotropic hypogonadism)
  • thyroid disease
  • hyperprolactinemia
  • diabetes
• Coronary artery disease
• Peripheral vascular disease
• Anemia
• Medications
• Smoking
• Alcohol abuse
• Surgical procedures
  • vascular surgeries
  • abdomino-perineal resection
  • radical prostatectomy
• Neurological conditions
• Psychiatric illness
  • anxiety disorder
  • depression
  • obsessive-compulsive disorder
• Injury

NOTE: The risk increases with age. Impotence is not a normal part of aging, however. Aging does not cause impotence.

Impotence can be classified as primary or secondary. A man with primary impotence has never had an erection sufficient for intercourse. This is rare. The more common condition, secondary impotence, is the loss of erectile function after a period of normal function. Except for impotence caused by injury or sudden illness, secondary impotence usually comes on gradually.

Treatment of secondary impotence is usually more successful than that for primary impotence because it is easier to restore function that has been lost than it is to discover why function has never occurred in the first place.

There are several components required for a satisfactory erection:

• A responsive emotional state of mind
• A normally functioning pituitary gland
• Adequate testosterone
• A healthy nervous system
• Adequate penile blood supply

Premature ejaculation (when orgasm comes on too quickly) is not the same as impotence. The couple should seek counseling for this problem, which is usually due to psychological factors.

Male infertility is also quite different from impotence. A man who is unable to maintain an erection may be perfectly normal in every other way and very capable of producing sperm that could fertilize an egg. An infertile man is usually able to maintain an erection, but he may be unable to father a child due to problems with sperm count or other factors.

In addition to the conditions listed as risk factors, causes of ED include the following:

• Penile implant or prosthesis that is not functioning properly
• Stress
• Recreational drugs such as cocaine, marijuana, alcohol, or heroin
• Liver disease, usually caused by alcoholism