CNR Center for Neuropharmacology, 'BB Brodie' Department of Neuroscience, University of Cagliari and Neuroscienze Scarl, Cagliari, Italy

Correspondence to: Dr L Pani, CNR Center for Neuropharmacology, Via Porcell, 4, 09124-I, Cagliari, Italy. E-mail: panil@unica.it

A large body of evidence has recently defined a field theory known as 'evolutionary mismatch', which derives its attributes largely from the fact that current environmental conditions are completely different from those in which the human central nervous system evolved. Current views on the evolutionary mismatch theory lack, however, any attempts to define which brain areas or neuronal circuits should be mostly involved in coding such misevolved traits and to what extent our neurobiological knowledge can be applied to the topographical localization of a specific psychopathology. In this respect the mesocorticolimbic dopaminergic circuits have long been misconceptualized as simple reward or reinforcement systems. Instead, they motivate and coordinate the functions of the higher brain areas that mediate planning and foresight and direct finalized movement in both animals and humans. These systems make animals intensely interested in exploring the world around them, but by the same means they also make them susceptible to the environmental stimuli that have been sought and consumed. It is has been speculated that the cortical dopamine targets that developed most recently in phylogeny are of particular functional value, and that the mesocorticolimbic dopaminergic system is involved in more complex integrative functions than previously assumed. In the present paper I will argue that some mental disorders may have their deep roots in the evolutionary mismatch between the normal physiology of the mesocorticolimbic dopaminergic system and the current environmental conditions in affluent societies. Molecular Psychiatry (2000) 5, 467-475.

evolution; limbic system; dopamine; stress; depression; emotions; Darwinian medicine