[Anxiety and depression in medicine: models and measurement]

Anxiety and depression are very common in patients with medical illness and can be associated to a reduction in quality of life and a poor clinical evolution. The actual concept of anxiety is based on many theoretical models as Goldstein's anxiety model, State/trate anxiety model, Lazarus' transactional stress model. The concept of depression is based on models such as Beck's Cognitive Model and Seligman's learned helplessness model of depression. The link between anxiety/depression and medical illness can be of two kinds: biological (immunological, neuroendocrine, inflammatory systems) and behavioural (coping strategies, adherence to medical advice and prescription, etc). The evaluation of anxiety and depression in medical patient can be done by many ways: taxonomic VS dimensional approach, auto VS heteroevaluation; specific instruments VS nonespecific instruments. All of these approaches are explored in this article. The only instruments used to evaluate anxiety and depression validated to the Portuguese population are: Hospital Anxiety and Depression Scale (HADS), o Beck Depression Inventory (BDI) (BDI) e o State Trait Anxiety Inventory (STAI). The only scale validated exclusively in the medical population, and that can overcome the influence that medical disease can have in depression and anxiety is HADS.