The British Journal of Psychiatry (2008) 192: 289. doi: 10.1192/bjp.192.4.289
© 2008 The Royal College of Psychiatrists
Psychosis: the price Homo Sapiens pays for language – in 100 words
Tim Crow
Age- and sex-dependent uniformity across populations of the psychotic
continuum reflects ontogeny of the cerebral torque. This
sapiens-specific evolutionary innovation identified four compartments of
association cortex as the language circuit: perceived speech > meaning >
thought > speech production. Symptoms (due to directional asynchronies of
callosal myelination) represent `leakages' – negative anterior, positive
posterior, linguistic to left, affective to right. The speciation
event occurred 160KYA in the Y copy (PCDHY) of the
ProtocadherinXY homologous gene pair with subsequent sequence change
in PCDHX. Thus, language, H. sapiens & predisposition to
psychosis resulted from a single chance event in a male, selected by
females.