Gad Saad Ph.D.

Homo Consumericus


Darwinian Roots of Obsessive-Compulsive Disorder

OCD: The misfiring of adaptive warning systems

Posted Oct 26, 2012

In 2006, I authored a commentary in Behavioral and Brain Sciences (Saad, 2006a) and an article in Medical Hypotheses (Saad, 2006b) in which I argued that many instantiations of OCD assort along universally sex-specific manners.  In other words, some obsessions and compulsions are more likely to afflict a given sex precisely because these map onto sex-specific concerns of evolutionary import.  I was providing a more granular explanation of more general evolutionary accounts of OCD (cf. Rapoport and Fiske, 1998; Abed & De Pauw, 1999; and Szechtman & Woody, 2004).  Take for example ruminative thinking, a form of OCD.  The specific contents of some culprit intrusive thoughts are much more likely to afflict one of the two sexes because they cater to Darwinian-based insecurities that are sex-specific (e.g., ruminative thoughts associated with the prospective loss of social status will be much more frequent among men). Similarly, obsessions and compulsions linked to the safety of one’s offspring are more frequent in women perhaps in part because of the evolutionary realities associated with parental investment theory and paternity uncertainty.  Finally, contamination fears are more prevalent among women, and these tend to wax and wane across the menstrual cycle in ways that are likely rooted in adaptive processes (e.g., the differential desire to avoid food pathogens as a function of a woman’s reproductive status; the shifting levels of disgust across the menstrual cycle).  See Saad (2006b) for relevant references.

Bottom line:  Evolutionary theorists have argued that OCD is the hyper-activation of warning systems that evolved to flag us against a wide range of environmental threats (physical, pathogenic, social, etc.).  In my work, I have argued that the symptomatology of OCD exhibits several universal sex-specific patterns that speak to sex-specific evolutionary threats.  To know whether an instantiation of OCD will garner a sex difference, one must gauge whether evolutionarily speaking the perceived threat was equally relevant to both sexes or not.

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