Erectile dysfunction can be caused by vasculogenic, neurologic, physical, hormonal, or other disorders that need to be treated.

Erectile dysfunction (ED—formerly called impotence) affects up to 20 million men in the US. The prevalence of partial or complete ED is > 50% in men aged 40 to 70, and prevalence increases with aging. Most affected men can be successfully treated.


There are 2 types of erectile dysfunction (ED):

  1. Primary ED, the man has never been able to attain or sustain an erection.
  2. Secondary ED, acquired later in life by a man who previously was able to attain erections.

Primary ED is rare and is almost always due to psychological factors or clinically obvious anatomic abnormalities.

Secondary ED is more common, and > 90% of cases have an organic etiology. Many men with secondary ED develop reactive psychological difficulties that compound the problem.

Psychological factors, whether primary or reactive, must be considered in every case of ED. Psychological causes of primary ED include guilt, fear of intimacy, depression, or anxiety. In secondary ED, causes may relate to performance anxiety, stress, or depression. Psychogenic ED may be situational, involving a particular place, time, or partner.

The major organic causes of ED are physiologic (organic) ones:

  • vascular disorders;
  • neurologic disorders.

These disorders often stem from atherosclerosis or diabetes.

The most common vascular cause is atherosclerosis of cavernous arteries of the penis, often caused by smoking, endothelial dysfunction, and diabetes. Atherosclerosis and aging decrease the capacity for dilation of arterial blood vessels and smooth muscle relaxation, limiting the amount of blood that can enter the penis.

Endothelial dysfunction is a disease of the endothelial lining of the small arterioles that reduces the ability to vasodilate when needed to increase blood flow. Endothelial dysfunction appears to be mediated by reduced levels of nitric oxide and result from smoking, diabetes, and/or low testosterone levels. Veno-occlusive dysfunction permits venous leakage, which results in the inability to maintain an erection.

Priapism, usually associated with trazodone use, cocaine abuse, and sickle cell disease, may cause penile fibrosis and lead to ED by causing fibrosis of the corpora cavernosa and thus impairment of the penile blood flow necessary for an erection.

Neurologic causes include stroke, partial complex seizures, multiple sclerosis, peripheral and autonomic neuropathies, and spinal cord injuries. Diabetic neuropathy and surgical injury are particularly common causes.

Complications of pelvic surgery (eg, radical prostatectomy [even with nerve-sparing techniques], radical cystectomy, rectal cancer surgery) are other common causes. Occasionally, transurethral resection of the prostate is a cause.

Other causes include hormonal disorders, drugs, pelvic radiation, and structural disorders of the penis (eg, Peyronie disease). Prolonged perineal pressure (as occurs during bicycle riding) or pelvic or perineal trauma can cause ED.

Any endocrinopathy or aging associated with testosterone deficiency (hypogonadism) may decrease libido and cause ED. However, erectile function only rarely improves with normalization of serum testosterone levels because most affected men also have neurovascular causes of ED.

Numerous drug causes are possible. Alcohol can cause temporary ED.


ED is determined in 3 ways including:

  • clinical evaluation;
  • screening for depression;
  • testosterone level.

Evaluation should include the history of drug (including prescription drugs and herbal products) and alcohol use, pelvic surgery and trauma, smoking, diabetes, hypertension, and atherosclerosis, and symptoms of vascular, hormonal, neurologic, and psychological disorders. Satisfaction with sexual relationships should be explored, including evaluation of partner interaction and partner sexual dysfunction (eg, atrophic vaginitis, dyspareunia, depression).

It is vital to screen for depression, which may not always be apparent. The Beck Depression Scale or, in older men, the Yesavage Geriatric Depression Scale is easy to administer and may be useful.

The examination is focused on the genitals and extragenital signs of hormonal, neurologic, and vascular disorders. Genitals are examined for anomalies, signs of hypogonadism, and fibrous bands or plaques (Peyronie disease). Poor rectal tone decreased perineal sensation, or abnormal bulbocavernosus reflexes may indicate neurologic dysfunction. Diminished peripheral pulses suggest vascular dysfunction.

A psychological cause should be suspected in young healthy men with abrupt onset of erectile dysfunction (ED), particularly if onset is associated with a specific emotional event or if the dysfunction occurs only in certain settings. A history of ED with spontaneous improvement also suggests psychologic origin (psychogenic ED).

Men with psychogenic ED usually have normal nocturnal erections and erections upon awakening, whereas men with organic ED often do not.

Please get in touch with us if you experience erectile dysfunction but don’t know the reason for that to occur. Our experts will make the proper diagnostic and select the required treatment.