The causes of erection problems can be physical, psychological, or a combination of the two. Physical causes of erection problems are more common in older men. They occur because of disorders that can affect the nerves and blood vessels responsible for causing an erection. 1  Physical causes of erectile problems include: 2  heart disease. 3  atherosclerosis (hardening of the arteries). 4  high blood pressure. 5  diabetes. 6  obesity. 7  high cholesterol. 8  Parkinson’s disease.