Diseases affecting the heart and the blood vessels
Heart and circulatory disorders cause the heart to become less capable as a blood pump and blood vessels can become narrowed and hardened.
As a result of reduced blood supply into the penis, it may not fill with enough blood required for an erection and/or blood in the penis may leak out faster than entering due to weakened compression on the veins which ultimately hinders a person’s ability to achieve an erection.
Diabetes
Elevated blood glucose levels damage blood vessels. Poor blood circulation can result in damage to nerves which are nourished by blood vessels. The most common causes of ED are the diseases of the blood vessels and nerve damage which often occur together.
Medications
Medications used in the treatment of high blood pressure, hypercholesterolemia, depression, psychosis, and anxiety are known to cause ED through well-defined mechanisms.
Smoking, alcohol, and drugs
Smoking, excessive alcohol use and recreational drug use are associated with a higher probability of ED.
Urologic disorders
Benign Prostatic Hyperplasia (BPH), which is the non-cancerous enlargement of the prostate tissue, is highly likely to interfere with erectile function. Pelvic surgery including some cancer-related surgeries of the prostate, bladder or bowel may result in nerve damage leading to ED.
Trauma
Injury to the spinal cord or the nerves necessary for the sexual function may disturb erectile activities.
Neurologic and psychiatric problems
Neurologic diseases, including early stages of Parkinson’s disease and Multiple Sclerosis, can result in reduced sensitivity, or reduction of signals to the penis to release the chemicals that initiate and maintain an erection. ED may be also an early sign of various psychiatric disorders.
Hormone imbalance
Deficiency of male hormones can reduce a man’s desire or interest in sexual activities.
Psychological problems
It is very common to see a combination of causes that affect psychological and physical well-being simultaneously. However, ED resulting from purely psychological causes are seen in less than 1 out of 10 men. ED can be the consequence of stress, depression, anxiety, posttraumatic stress, relationship problems, embarrassment, feelings of guilt, and other psychosocial issues. When a man has difficulty getting an erection, whatever the cause, he will often experience a pressure to perform. This can lead to a feeling of inadequacy and a sense of loss of manhood (called performance anxiety). These are all common emotions for most of the men with ED, which may lead the affected people into a vicious cycle of anxiety and ED.