ED can be caused by physical and psychological factors.
The physical factors include:
- Certain prescription drugs like blood pressure drugs and antidepressants
- Chronic illnesses like diabetes, cardiovascular (heart-related) diseases, hypertension (high blood pressure), nerve damage and multiple sclerosis (an autoimmune disease affecting the nerves). These illnesses can affect the nerves and the blood flow to the penis, and lead to ED.
- Low levels of testosterone, and injured or damaged nerves and arteries near the penis (eg. due to pelvic surgery)
- Poor lifestyle, which includes smoking, drinking too much 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/or depression
The prevalence of ED increases with age, from 5% in men aged 45 years to 50% in men aged over 75 years.