What is erectile dysfunction (ED)?

Medically, erectile dysfunction (ED) is defined as the inability to both achieve and maintain a penile erection adequate for satisfactory sexual intercourse.ⁱ Occasionally, ED is referred to as impotence, even though this term is now considered outdated. ED is highly prevalent in the general population. One study showed that, in the U.S., 18.4 percent of males 20 years or older have this condition.ⁱⁱ

Erectile dysfunction is more common with age, and increasing age is the principal risk factor for ED.ⁱⁱⁱ While there is a range in the literature, one study of 2,156 males found that 5 percent of males between the ages of 20 and 39 had ED, compared to 70 percent of males aged 70 and older.^iv Globally, the number of males with ED is increasing, which is thought to be due to the aging population.

Although the incidence of ED increases with age, a study of 439 patients found that 26 percent of males seeking medical attention for ED were 40 years old or younger.^v Experiencing ED on occasion is not uncommon. For example, some males may have ED symptoms during stressful times or due to performance anxiety. However, if ED occurs regularly, that person may need medical treatment and could have underlying health problems that need to be addressed by a healthcare provider.

What are the symptoms of erectile dysfunction?

The main symptom of erectile dysfunction (ED) is the inability to achieve or maintain an erection that is sufficiently rigid or lasts long enough for sexual intercourse.^vi

Most males with ED also have secondary issues, such as symptoms of anxiety or depression because they believe their sexual performance is lacking.^vii These symptoms can have a detrimental effect on the quality of life of both the patient as well as any current or potential partners.

While not a symptom of ED itself, ED is commonly associated with lower urinary tract symptoms in patients with a large prostate gland.^viii These symptoms are usually caused by the non-cancerous enlargement of the prostate (called benign prostatic hyperplasia (BPH)), a condition which is common in older males. Lower urinary tract symptoms include urinary hesitancy, poor or intermittent stream, straining, and incomplete emptying. These symptoms occur due to the enlarged prostate partially blocking the urethra, which is the tube that carries urine and semen.

ED can also be associated with cardiovascular issues, as discussed below.

What causes erectile dysfunction?

The causes of erectile dysfunction (ED) are classified in three ways:

• ‍Organic: When the ED has an underlying physical cause.
• ‍Psychogenic: When the ED has a psychological origin.
• ‍Mixed: When the ED is caused by both organic and psychogenic concerns.

Organic causes of ED are thought to account for over 80 percent of cases, though psychogenic ED is more common in younger males.^ix‍

Organic causes of erectile dysfunction^x

There are four main causes of organic ED: vasculogenic, neurogenic, endocrinological, and drug induced.

Vasculogenic causes

The most common cause of erectile dysfunction is vasculogenic, meaning there is damage to the arteries or veins (the vascular system). Increased blood flow to the penis is important for erectile function, therefore damage to or blockage of the blood vessels supplying the penis can impact its ability to stay rigid.

Here are some common vasculogenic causes:

• ‍Atherosclerosis: The build-up of plaques in the arteries can lead to blockage and low flow. Atherosclerosis can occur in vessels throughout the body, which is why ED is associated with other cardiovascular problems such as heart attacks and strokes.
• ‍Pelvic trauma: Injury can prevent penile veins from “closing off” outflow during an erection, which can lead to ED.
• ‍Direct penile trauma: A penile fracture or a priapism (erection lasting longer than four hours), for example, can lead to permanent vascular injury to the penis.

Neurogenic causes

Neurogenic erectile dysfunction is caused by a dysfunction of the nervous system. It may be related to the central nervous system (brain or spinal cord) or to the peripheral nervous system (nerves that come out of the spinal cord).

These are common central nervous system causes of ED:

• Spinal cord injury or surgery
• Stroke
• Epilepsy
• Parkinson’s disease
• Multiple sclerosis (MS)  

Here are some peripheral nervous system causes of ED:

• Pelvic surgery (such as prostate removal)
• Diabetes

Endocrinological causes

Dysfunction or dysregulation of the endocrine system, which controls hormones in the body, can cause erectile dysfunction.

These are some common endocrinological causes:^xi

• Diabetes, which can also cause neurogenic ED
• Low testosterone
• Hyperprolactinemia, which results in an increased level of prolactin (a hormone that is produced in the brain and induces lactation)
• Chronic systemic illnesses such as liver or kidney failure, which can cause endocrine system problems (such as low testosterone)
• Obesity, which is associated with low testosterone

Drug-induced causes

Certain medications and recreational drugs can contribute to erectile dysfunction. Prescription medications such as anti-androgens (e.g., GnRH agonists, spironolactone), antihypertensives (e.g., thiazide diuretics), antiarrhythmics (e.g., digoxin), statins, and antidepressant medications (e.g., SSRIs, TCAs) can lead to ED. Recreational drugs such as marijuana, opiates, cocaine, nicotine, and alcohol are also associated with ED.

Psychogenic causes of erectile dysfunction

Psychogenic causes of ED often involve a complex interaction of psychological factors. Here are some factors that may contribute:^xii

• Traumatic past experiences
• Acute relationship problems
• Performance anxiety
• Major life stressors
• Mental health conditions

How is erectile dysfunction diagnosed?

To diagnose erectile dysfunction, a thorough history and physical examination are typically conducted. The full testing process may involve everything from discussing medical history and sexual history with a health professional to undergoing blood tests or imaging studies that may indicate signs of physical issues.

Medical history assessment

During a medical history assessment, a physician will take a detailed medical history from the patient and will ask questions pertaining to erectile dysfunction. These questions are also useful to distinguish between ED and other types of sexual dysfunction, such as decreased libido or premature ejaculation. In addition, the assessment can determine the presence of risk factors for other diseases that can cause ED, such as diabetes or cardiovascular disease.^xiii

A psychological assessment may also be warranted, as psychological factors often contribute to ED. This portion of the assessment may involve discussing interpersonal conflict or relationship factors that may influence ED.

During the assessment, the care provider may also look at what oral medications the patient may be taking, including over-the-counter drugs. Lifestyle factors are often discussed, too, such as exercise and nutritional habits.

International Index of Erectile Function (IIEF) or Sexual Health Inventory for Men (SHIM) screening

A validated screening tool such as the International Index of Erectile Function (IIEF) or Sexual Health Inventory for Men (SHIM) may also be used to detect ED.^xiv The IIEF is a self-administered questionnaire consisting of 15 questions answered by the patient, while the SHIM is a modified, five-question version of the survey.^xv A sexual history may also be obtained through a validating screening tool such as the Brief Sexual Symptom Checklist.^xvi

Physical exam and other testing for erectile dysfunction 

The physical examination involves evaluating the genitals, including the penis and scrotum, for lesions, scars, and plaques, as well as the positioning of the urethral opening (where urine and semen exit the body).^xvii During the exam, the physician will also evaluate the size of the testicles and look for any other changes. They may also evaluate the cardiovascular system and screen for physical indicators of decreased testosterone or hyperprolactinemia.

Blood tests may be performed to examine biological markers for underlying conditions such as low testosterone or other hormonal changes.

In some cases, additional testing may be recommended to determine the cause of erectile dysfunction. A nocturnal penile tumescence (NPT) test may be performed during a sleep study to determine how many erections a male has while he is asleep. If a male is not having natural erections during sleep, it can be an indicator of erectile dysfunction. Currently, NPT is not commonly performed due to difficulty administering the test and a high rate of false negatives.

Other testing includes a penile injection (called an intracavernosal injection (ICI)) administered in a doctor’s office with a medicine to stimulate erection. This test can allow physicians to determine the cause of ED and to assess penile curvature (Peyronie’s disease). A special ultrasound test called a penile duplex ultrasound may also be used to check blood flow to and from the penis before and during the induced erection.^xviii

How does erectile dysfunction impact fertility?

Fertility may be affected by erectile dysfunction, especially in more severe cases where it is an ongoing problem.  A 2018 study of 4,299 Chinese males found that 34.9 percent of males in infertile couples had mild ED and 2.6 percent had severe ED, according to IIEF criteria.^xix

Here are the main reasons why ED impacts fertility:

• ‍Insufficient penetration: Even though an erection is not necessarily required for ejaculation to occur, erectile failure can inhibit sufficient penetration. If the ED is severe, resulting in an absent erection or consistent inability to achieve an erection that is sufficient for penetrative intercourse, sperm transport to a partner’s cervix will be impaired, thereby impeding conception. For this reason, erectile dysfunction is classified as a sperm transport disorder.^xx‍
• Ineffective ejaculation: The inability to release semen (which contains sperm) effectively in cases of erectile dysfunction can decrease fertility, even though the ability to produce sperm is not usually impaired.
• ‍Reduced frequency of sex: Patients with impaired erectile function have higher odds of less frequent sexual intercourse, which is associated with reduced fertility.^xxi

While fertility can be affected by erectile dysfunction, many couples do see success with one of the available treatment options for ED. Many males with ED have underlying health problems that can be addressed successfully, and lifestyle changes can also make a drastic difference.

What erectile dysfunction treatment options are available and how successful are they?

Seeking treatment for erectile dysfunction can be intimidating, but several treatment options have been shown to be effective for helping males achieve erections that are satisfactory for sexual intercourse. Doctors treat erectile dysfunction according to the underlying cause, and some males will need a multifaceted approach to achieve the best treatment outcomes.

Treatment of organic erectile dysfunction

Erectile dysfunction that has an organic (physical) cause will be treated with pharmacotherapy, lifestyle changes, dietary supplements, or certain medical procedures.

Pharmacotherapy

Certain prescription medications or types of drug therapy may be effective for treating erectile dysfunction and increasing blood flow to the penis. Oral phosphodiesterase-5 (PDE5) inhibitors are considered the first-line treatment for erectile dysfunction and are generally held to be a very successful.^xxii,xxiii These are the major PDE5 inhibitors:

• Sildenafil (Viagra®)
• Tadalafil (Cialis®)
• Vardenafil (Levitra®)
• Avanafil (Stendra®)^xxiv

A study on sildenafil use among males with infertility showed that it significantly improved erectile function and improved ejaculatory dysfunction by 64 percent.^xxv

While effective, prescription drugs only help with sexual function. They do not directly help with sexual arousal and must be used in combination with sexual stimulation in order to work. However, many males find that once they get an erection with the help of a prescription drug, the sexual arousal aspect comes more naturally, and ejaculation is easier because sensitivity is enhanced with better blood flow.

Lifestyle changes

Lifestyle modifications, including stopping smoking, decreasing alcohol intake, losing weight, and increasing physical activity have been shown to improve erectile function,^xxvi though they may take up to two years to work.^xxvii

If a healthcare provider provides medical advice that involves making lifestyle changes, these recommendations should be taken seriously.

Dietary supplements

Some dietary supplements may offer benefits for males who have erectile dysfunction, even though the results can vary depending on the formula. One example of a dietary supplement for ED is arginine (also called L-arginine), a vasodilator that may help open blood vessels and encourage blood flow to the penis. Arginine has been shown to be a promising supplement option for ED, but further research is needed.^xxviii

Procedural and other types of therapy

There are several medical procedures and therapies available to help with erectile dysfunction:

• ‍Intracavernosal injection (ICI) and transurethral therapy: Medicine is either injected into the penis (in the case of ICI) or inserted into the tip of the penis (transurethral therapy) to trigger an erection.^xxix These treatments can be attempted if a patient does not have success with oral medications, such as PDE5 inhibitors (e.g., Viagra®, Cidenafil®).
• ‍Vacuum constrictive device: This device brings blood supply into the penis and constricts the base of the penis with an elastic band to retain blood and allow for an erection. While vacuum and constrictive devices do change how blood flows to the erection chambers of the penis and may create a temporary erection, the risk of blood vessel or nerve damage with improper use may exacerbate the problem over time. Therefore, males should seek medical advice, use caution, and invest in quality-made devices when using vacuum pumps or constricting bands to treat ED.
• ‍Penile prosthesis: Regarded as a last resort for ED, it involves a surgical procedure in which a penile prosthesis is inserted inside the penis. The device can be inflatable, with a pump in the scrotum that is used to inflate the device with fluid to achieve an erection. There are also malleable devices, which are not inflatable and are always in a semi-rigid state. Patient satisfaction rates are over 90 percent for treating ED with an inflatable penile prosthesis.^xxx However, since penile prosthesis implantation requires surgery and involves the permanent insertion of an artificial device, there are potential risks. The most common risks include bleeding, infection, migration of the device including erosion into the urethra or skin, device failure, and penile shortening or pain. As the inflatable devices are mechanical, they can also fail with time and may need to be replaced.
• ‍Hormone therapy: Testosterone therapy or other hormonal therapies may be recommended if blood tests reveal low testosterone levels. Often, if a patient has low testosterone as a cause for his ED, he will also have additional symptoms of low testosterone including low libido (desire for intercourse) and fatigue. Even though low testosterone can be linked to ED, low testosterone or other endocrine system disorders are rarer causes.^xxxi  It is important to note that treatment of low testosterone with testosterone therapy can cause male infertility. If a patient has low testosterone and wishes to preserve his fertility, alternate treatments with different hormonal medications (such as selective estrogen receptor modulators, gonadotropins, or aromatase inhibitors) are typically prescribed.^xxxii

Treatment of psychogenic erectile dysfunction

Psychogenic erectile dysfunction is best treated with psychological interventions. Patients meeting clinical criteria for anxiety or depression may benefit from pharmacotherapy with selective serotonin reuptake inhibitors (SSRIs). However, SSRIs are also a risk factor for the development of ED. A 2016 study suggests that adding an additional medication, bupropion, may improve sexual dysfunction associated with SSRIs.^xxxiii

Additionally, psychotherapy may improve erectile dysfunction, and there is clinical evidence to suggest that group psychotherapy can be helpful.^xxxiv Males who have experienced past trauma, have been diagnosed with a mental health condition such as depression, or otherwise struggle with sexual arousal, may benefit from seeking help from a mental health professional.

What other risks/complications are associated with erectile dysfunction?

Males who deal with erectile dysfunction can face further issues beyond just the physical side effects or problems with sperm delivery. Erectile dysfunction has a significant psychosocial impact on patients and has been shown to be seriously distressing to individuals who experience it.^xxxv These impacts include lower self-esteem as well as negative effects on relationships.

In addition, erectile dysfunction may be the first evident symptom of cardiovascular disease. Males with ED have a higher risk of cardiovascular events compared to males without ED.^xxxvi A 2013 systematic review indicated that ED can be a predictor of heart disease, and the study authors proposed that ED and cardiovascular disease should be considered as two different manifestations of the same overall disorder.^xxxvii

Relatedly, a meta-analysis of 92,757 patients across 14 studies showed that patients with ED had a 62 percent increased risk of myocardial infarction (heart attack), and 25 percent increased overall mortality compared to people who did not have ED.^xxxviii Because of this correlation, males with ED often require a cardiovascular work-up to rule out concurrent cardiovascular disease.^xxxix

Conclusion

Erectile dysfunction (ED) is a common sexual health problem for males; it is also highly treatable. If an individual suspects that he has ED, seeking medical advice is always recommended. ED can be an indication of other health problems, such as high blood pressure or another vascular disease, heart disease, or even prostate problems. Everything from prescription drugs to penile implants may be used to treat ED; some over-the-counter drugs and medical treatments are more effective than others.

ED can impact fertility, but primarily in an indirect way due to the physical inability to maintain an erection for ejaculation and sperm delivery. Anyone experiencing ED that is interfering with the ability to conceive should speak to a doctor who can provide medical advice, discuss options, and potentially help find a solution.