Schizophrenia Research Trends

130Joseph Polimeni and Jeffrey P. Reissones to spearhead spiritual rituals.To summarize our hypothesis; schizophrenia is viewed as a vestigial phenotype thatpossesses several adaptive features for hunting and gathering societies. The phenomenaknown to us, as schizophrenia, would have generated shamans for hunting and gatheringtribes through a group selection evolutionary process. Shamanism could perhaps be the mostcompelling example of cognitive-behavioral task specialization in human beings – analogousto task specialization in honeybees and ants. The primary function of shamanism would be tospearhead magicoreligious rituals. The adaptive function of spiritual rituals would be tohomogenize tribal opinion around enigmatic events and foster group cohesion.In this context, positive symptoms of schizophrenia become evolutionarily beneficial.Delusional or hallucinatory experiences frequently contain magicoreligious or paranoidthemes – abstractions of potential importance to hunting and gathering tribes. The dramaticand inscrutable quality of psychotic experiences would cast an indelible impression uponothers, thereby reinforcing the notion of unfathomable supernatural forces. The looseness ofassociations typically observed in psychosis could generate possible creative solutions attimes when the integrity of the tribe was critically challenged. Paranoid ideation has its owngroup-selected advantages. In the anthropological literature, there are examples of paranoidideation in specific individuals facilitating unprovoked warring raids upon neighboring tribes[97,111]. Although unjustified and horribly brutal, these surprise attacks may nonetheless bean adaptive survival strategy for attacking tribes.Negative symptoms of schizophrenia such as social withdrawal, avolition and alogiawould erode basic human qualities, thereby giving credence to the belief that the afflictedindividual was truly a vehicle of supernatural phenomena. Poverty of thought, a pervasivefeature of schizophrenia, could attenuate logical analyses of discrepant information andfacilitate delusional thinking.CONCLUSIONDarwin was prescient regarding the possible importance of evolutionary theory to mentalconditions [16]:“In the distant future I see open fields for far more important researches. Psychology willbe based on a new foundation, that of the necessary acquirement of each mental power andcapacity by gradation. Light will be thrown on origin of man and his history.”(Origin of theSpecies, 1859)Evolutionary principles could be relevant to schizophrenia due to its presumed geneticbasis and supposed long history. Although neglected prior to the 1960’s, a number ofevolutionary based hypotheses have since emerged speculating on the possible origins ofschizophrenia. Incorporating evolutionary perspectives can only enhance our understandingof schizophrenia.