Allostasis and neuroprogression in major psychiatric disorders

The hypothesis of allostasis may be a pertinent model to explain the course of psychiatric illnesses by means of stress and to explain the dimensional impact of mental disorders on the organism, not only on the brain but on other organs of the body. Moreover, it is also suitable to explain the neuroprogression of psychiatric disorders from a ‘wear and tear’ approach, detailing the progressive increase of cognitive impairment, accelerated ageing, and rates of medical and psychiatric comorbidities that patients with major psychiatric disorders have. In this chapter, the concepts of allostasis, allostatic load, and allostatic overload are detailed from a neuroprogressive approach and their application to neuropsychiatric illnesses is explained in relation to anxiety disorders, affective disorders, such as unipolar depression and bipolar disorder, and psychotic syndromes.