Introduction

Increasingly, psychological disorders are being revisited from evolutionary perspectives (Stevens and Price 1996). For those new to reconceptualizing illness in evolutionary perspectives, a few cautions are needed. Darwin did not view evolution as following any predetermined design or direction – there is no end goal (Birx 1997). Darwin had misgivings about the term ‘evolution’ because of its potential to be misinterpreted. Evolution is neither static nor without error. The environmental background on earth has been, and will be, forever changing until the planet meets its eventual demise, let us hope in the distant future.