Erectile disorder is when a man cannot maintain an erection of his penis for an adequate time. This can be due to many causes in the nervous system, blood circulation or hormonal imbalance. For older men, this may be biological-based. This is because the neurons of older people are less functional relative to younger men. Also, ailments like diabetes and high blood pressure could block the flow of blood. For younger men, it is more psychological-based due to tension or anxiety.