Why is it that some of us have more pain, more fatigue, and more gastrointestinal trouble than others? Is it possible that there are brain mechanisms and psychological mechanisms that make some people sensitized to specific complaints? In this concluding paper we review the historical and theoretical background, discuss the evidence and theoretical positions in the contributions, and draw some conclusions. Traditional psychosomatic models had less predictive value and less therapeutic importance than what was hoped for. The main problem with these models was the lack of a pathophysiological explanation for why psychological problems could be related to somatic disease. Sustained arousal or "allostatic load" offers more plausible and acceptable mechanisms for pathology, and, to some extent, for sensitization and illness. The combination of cognitive psychology and neurophysiology offers a model for somatic pathology, and, perhaps more important, also for the understanding of subjective complaints and illness.