Tannock, 2002), or, following Almasy & Blangero (2001), require that an endophenotype ‘should be continuously quantifiable, should predict disorder probabilistically and should be closer to the site of primary causative agent (whether genetic or environmental) than to diagnostic categories’. It has also been suggested, that ‘priority should be given to endophenotypes that are based or anchored in neuroscience’ (Doyle et al. 2005).