[Excerpt] What we will do here is set out some models of disease, and then apply them to some clinical problems to see how the models shape up. The models of disease we discuss are not all mutually exclusive, but different ways of viewing the clinical problems we encounter. The models include:
*Cause and effect models, and their several variants;
*‘edge of the distribution’ illnesses (also known as ‘spectrum disorders’);
*Spontaneously remitting and self-perpetuating illnesses; and
*‘alternative’ medicine models.
These are all ‘transparent box’ approaches to disease: that is, a model of how the disease works, which in turn should suggest how we might treat it. But we can also take a ‘black box’ or empirical approach, which recognises a pattern of illness, and base treatment on what has worked with similar patterns in the past. These approaches are complementary. The models can also mislead us, and so we will also discuss the important topic of ‘non-disease’, that is, conditions that now or in the past have been given the label of a ‘disease’ but where the condition is a harmless variant of normal, or a misunderstanding of causation.