Psychological problems, neurological problems, abnormalities in blood ﬂow, damage to the genital organs, hormonal imbalance, and the use of drugs or medications—all can interfere with any of the four stages of normal sexual func- tion. Erectile dysfunction occurs when one or more of these factors persistently interfere with the ability to achieve and maintain an erection sufﬁcient to com- plete sexual intercourse.
Erectile dysfunction is often called impotence. Some experts object to the term “impotence” because of its negative implications and lack of precise mean- ing. The term “erectile dysfunction” is now
used. Erectile dysfunction is deﬁned as the inability to achieve or maintain an erection as part of the overall multifaceted process of sex- ual function. This deﬁnition deemphasizes intercourse as the essential or only aspect of sexual life and gives equal importance to other aspects of male sexual behavior.
At some time in their life, all men experi- ence erectile problems. But for 30 million men in the United States, erectile dysfunction is a chronic, persistent problem. This number includes about 10 percent of the entire male population and 35 percent of men over 60. Fewer than 5 percent of men with erectile dys- function seek treatment for this condition.
There are different levels of erectile dys- function:
• a total inability to achieve erection
• the occasional ability to achieve erection
• an inability to maintain erections
• the ability to achieve erection, but inability to control ejaculation
Most cases of erectile dysfunction are treat- able and are not the result or inevitable conse- quence of aging. The response in the penis that results in a normal erection depends on healthy nerves, blood vessels, muscles, and ﬁbrous tis- sues, as well as on adequate blood levels of cer- tain hormones, such as testosterone. Damage, injury, or malfunction in any of these areas can lead to erectile dysfunction. A number of phys-ical factors such as disease or surgery, as well as psychological factors, can also cause erectile dysfunction. In the past, it was believed that erectile dysfunction was largely caused by psychological problems. Today most experts agree that, in 85 percent of cases, erectile dysfunction is the result of physical factors, most of which can be treated.
The following conditions can cause erectile dysfunction:
• Diabetes. High levels of blood sugar associated with diabetes can damage small blood vessels and nerves throughout the body, including those in and around the penis. Diabetes can interfere with the nerve impulses and the blood ﬂow necessary to produce an erection. About 60 percent of men with diabetes experience erectile dysfunction.
• Heart disease. Atherosclerosis, which causes hardening and narrowing of the arteries, increases with age. Over time it can reduce blood ﬂow to the penis and lead to erectile dysfunction. It accounts for most cases in men over 60 years of age.
• Leaking veins. When veins in the penis are not compressed during an erec- tion, a vein can leak, leading to erectile dysfunction. A leak can be the result of injury, disease, or damage to the veins in the penis.
• Neurological injuries or disorders. Spinal cord and brain injuries, including paraplegia and stroke, can cause erectile dysfunction when they interrupt the transfer of nerve impulses from the brain to the penis. Other nerve disorders, such as multiple sclerosis, Parkinson’s disease, and Alzheimer’s disease, may also result in erectile dysfunction.
• Drugs. More than 200 prescription medications may directly cause or con- tribute to erectile dysfunction. Among these are drugs for high blood pressure, antidepressants, tranquilizers, sedatives, and a number of over-the-counter medications. Long-term, excessive consumption of alcohol and use of illegal drugs such as heroin and cocaine also can cause erectile dysfunction.
• Hormonal imbalances. Hormonal disorders account for fewer than 5 percent of cases of erectile dysfunction. Testosterone deﬁciency, which is rare, can result in the loss of libido (sexual desire). An excess of the hormone prolactin, produced by tumors in the pituitary gland, reduces levels of testos- terone. Kidney and liver disease also may lead to hormonal imbalances that contribute to erectile dysfunction.
• Peyronie’s disease. This is a relatively rare inﬂammatory condition that causes scarring of the erectile tissue in the penis. The scarring produces a curvature in the penis that can interfere with sexual function. In addition, it may cause erections to be painful.
• Pelvic surgery. With surgery of the colon, prostate, or bladder, the nerves that control the ﬂow of blood into and out of the penis may be cut or removed. These nerves can be permanently damaged in men who have undergone radiation therapy for prostate or bladder cancer. Although these nerves do not
control sensation in the penis and, therefore, are not responsible for orgasms, they inﬂuence the ﬁrmness of the penis during erection.
Some surgeons may try to spare nerve function during these procedures, with the hope that any sexual function problem will be temporary. Usually it takes 6 to 18 months for erections to return. Partial erections may return sooner. If they do, it could be a sign that complete erectile function will even- tually return.
• Pelvic injury. A minor injury to the pelvic area, including a fall or blow to the hip while playing sports, or a very long bike ride, can sometimes numb the nerves around the penis and block their normal functioning. A day of rest is usually enough time for the nerves to recuperate.
• Psychological causes. Even though most cases of erectile dysfunction are the result of physical factors, psychological factors should not be overlooked. The most common psychological cause of erectile dysfunction is performance anxiety, a man’s fear that he will not be able to perform sexually. Anxiety may lead to an initial failure, which increases the anxiety, resulting in a cycle that leads to future failures to achieve an erection.
Stress, tension, depression, worry, guilt, and anger can also inhibit sexual performance. These psychological factors may occur secondary to and possi- bly as a result of the physical causes. They may magnify the impact of erectile dysfunction resulting from physical causes.
The ABCs of Erection
n erection occurs when blood is pumped into the penis. The more blood that ﬁlls the penis, the harder the erection. Failure to achieve erection occurs when the penis does not ﬁll or
remain ﬁlled appropriately.
The penis has three chambers: two chambers called the corpora cavernosa, and one called the corpus spongiosum. The corpora cavernosa run the length of the penis and are ﬁlled with spongy tissue that contains smooth muscle, ﬁbrous tis- sue, open spaces, veins, and arteries. A strong membrane, the tunica albuginea, surrounds the corpora cavernosa. The corpus spongiosum, which contains the urethra, runs along the under- side of the corpora cavernosa.
Erection begins when a man receives an erotic sensory or mental stimulus. The brain sends impulses to the nerves around the penis, which cause the many tiny muscles of the spongy cor- pora cavernosa to relax, allowing blood to ﬂow in and ﬁll the open spaces inside the corpora cav- ernosa. This blood creates pressure in the corpora cavernosa, which makes the penis expand and compress the veins that normally allow the blood to drain. By helping to trap the blood in the cor- pora cavernosa, the tunica albuginea sustains the erection. Erection is reversed when the muscles in the penis contract, preventing blood from ﬂowing in and opening the channels that allow blood to ﬂow out.