Sexually compulsive behaviour can be pleasurable both in the preparation of the act and in the doing of it. The pleasure is in the intensity of the build-up, the loss of self in the act, the power of the orgasm and the alleviation of any negative feeling states that preceded it. We are biologically programmed to be sexual and the brain chemistry of arousal shuts down cognitive function. Sexual addiction is a short-term, powerfully rewarded behaviour. The reward is so powerful that its strength often eclipses any negative after-effects of the behaviour.