ED can be caused by physical and psychological factors.
The physical factors include:
- Certain prescription drugs such as blood pressure drugs and antidepressants
- Chronic illnesses such as diabetes, cardiovascular (heart-related) diseases, hypertension, nerve damage and multiple sclerosis. These illnesses can affect the nerves and the blood flow to the penis.
- Low levels of testosterone, and injured or damaged nerves and arteries near the penis (due to pelvic surgery)
- Poor lifestyle, which includes smoking, excessive consumption of alcohol, drug abuse, lack of physical activity, and being overweight.
The psychological factors include:
- Fear of sexual failure
- Low self esteem
- Previous traumatic sexual experiences
- Stress, anxiety, and depression
The prevalence of ED increases with age, from 5% in men aged 45 years to 50% in men aged over 75 years.