The last issue of the journal Progress in Neuro-Psychopharmacology and Biological Psychiatry has a very interesting special issue on how evolutionary theory and psychology can be integrated into psychiatric theory about mental disease. It’s also called “evolutionary psychiatry“.
OK, you might ask; we can accept that evolutionary theory can explain why we behave as we do today, i.e. normal cognition and behaviour. But psyhiatric disease? Is this an attempt to explain the evolution of a disease? The straightforward answer is a resounding “no”. Evolutionary approaches to disease – including mental disease – is an attempt to describe and explain the design characteristics that make us susceptible to the disease (from Nesse & Williams, 1996). The evolutionary trajectories of humans is far from a travel towards perfection. We are full of errors and somatic and mental shortcomings – and the appendix, near-sightedness, and a bottleneck attentional system and the like are examples of this.
Another important issue is that the border between normal and abnormal psychology is becoming increasingly muddled. That may sound as a problem, but it’s actually caused by a change in our understanding of how our minds come to be, and especially how normal variation extends into pathological domains. In this sense, it’s hard to draw waterproof boundaries between normal and abnormal psychology. We work on a continuum, and the branch of modern evolutionary psychiatry makes a good case for such an approach.
Here is the introduction by Dan J. Stein:
Darwin wrote extensively on the implications of evolutionary theory for understanding human psychology, and made a special effort to gain access to observations on the insane. Pioneering ethologists, such as Tinbergen, emphasized the value of their work for understanding psychiatric disorders. Today, evolutionary psychology has become an accepted scientific field, and the area of evolutionary psychiatry has similarly shown increasing maturity. This special issue of “Progress in Neuropsychopharmacology and Biological Psychiatry” provides an opportunity to review some of these developments.
An introductory paper by Stein summarizes some of the history of evolutionary psychiatry in general, and considers its application to psychopharmacology in particular. Panksepp then outlines a number of conceptual issues at the heart of evolutionary psychiatry, arguing that there are flaws in much of the work that has been undertaken in evolutionary psychology and psychiatry, and proposing a novel way forwards. These introductory papers emphasize the possibility that the focus of evolutionary psychiatry on distal mechanisms can be usefully integrated with advances in our understanding of the proximal mechanisms that underpin psychopathology.
Several of the contributions in this issue go on to exemplify the application of the constructs of evolutionary psychiatry to particular mental disorders. Crow and Burns put forward different evolutionary approaches to schizophrenia, Allen and Badcock review evolutionary approaches to depression, Bracha focuses on the anxiety disorders, Feygin and colleagues on obsessive-compulsive disorder, and Baron–Cohen on autism. Although there are important challenges for evolutionary psychiatry going forwards, as the sophistication of its concepts and methods increases, so likely will its influence on the understanding of psychopathology.
A number of authors in the area of evolutionary psychiatry are also interested in more fundamental issues in evolution of brain and behavior. Thus, Crow is crucially concerned with the evolution of language, Burns emphasizes the evolution of social cognition, Baron–Cohen’s work touches on the importance of gender differences in systematizing and empathizing abilities, and Feygin and colleagues’ work addresses the evolutionary bases of religious ritual and loving attachment. Indeed, there is an argument that fundamental progress in evolutionary theory will be reliant on the resolution of key questions about mind and its illnesses.