Erection problems may be caused by physical problems related to the blood vessels, nerves, and hormones. Or they may be caused by mental health issues.

Normally, an erection occurs when your imagination or senses (vision, hearing, touch, smell, taste) are stimulated. You then get aroused. Your central nervous system sends nerve impulses that increase blood flow to your penis.

Physical problems

Physical problems are often the cause of erection problems in men age 50 or older. These problems include:

• Side effects of medicines. This includes some medicines used to treat benign prostatic hyperplasia (BPH), depression, and prostate cancer. In some cases, you may be able to change the dose of the medicine or to use another medicine. Talk to your doctor.
• The use of tobacco, alcohol, or illegal drugs. Stopping or reducing the use of these substances may make the erection problem less severe.
• Problems with the blood vessels. These problems may prevent blood from filling the penis or from staying there long enough to keep an erection. For example, long-term high blood pressure can cause damage to blood vessels and lead to erection problems.
• Problems with the nerves (neurologic problems). These may prevent arousal signals from traveling from the brain and spinal cord to the penis.
  • Nerve disorders such as Parkinson's disease, Alzheimer's disease, multiple sclerosis, and stroke may interfere with a man's ability to have an erection. And they may lower sexual desire.
  • Nerve damage from diabetes, complications from surgery, and spinal cord injury also may cause problems.
• Problems with the structure of the penis or its surrounding tissues.
• Hormones, such as a low level of the hormone testosterone.
• Pelvic injuries and complications of prostate or other surgeries. They can interfere with nerve impulses or blood flow to the penis.

Psychological causes

Mental health issues seem to be involved in many cases of erection problems. These issues include:

• Depression (which also has a physical component).
• Anxiety.
• Stress.
• Grief.
• Problems with current or past relationships.

These things interfere with the erection process by distracting the man from things that would normally arouse him.

Erection problems in men younger than 40 who have no physical risk factors are more likely to be caused by mental factors than physical causes.