Physical organic causes are now thought to account for most cases of erectile dysfunction (ED), although there is often a psychogenic contribution to the condition. Atherosclerotic disease is estimated to account for 40% of ED in men over 50 years, and vascular disease, including diabetes, is a common cause of ED. ED may be considered an early marker for cardiovascular disease. Ageing is a strong risk factor, and both psychological conditions such as anxiety and depression and neurological conditions such as Parkinson's disease are also common risk factors. Pelvic surgery, with which there is a risk of nerve damage, may also result in ED. Other causes include endocrine disorders, and interactions from prescribed drugs such as antihypertensives, antidepressants, antipsychotics, hormone treatments, and histamine H 2 antagonists such as cimetidine. Anatomical features and anatomical conditions such as Peyronie's disease are a less common cause of ED.