I don't know, but I think "insanity" forms a continuum. At one end are individuals like Hitler and Stalin and Mao and Pol Pot, individuals who think happiness and the meaning of life comes from destroying the lives of tens of millions of men, women and children through genocide or campaigns of forced starvation. Most people never sink to this level of insanity. I guess insanity, whatever that means, has a genetic and an environmental component. I am often wrong about things and perhaps I am wrong about all this too.