Homosexuality is inherited in most cases, though there are incidents of people turning homosexual due to psychiatric trauma or mental illness. In evolution, homosexuality has only one potential purpose in the over all survival of the species and that is population control. Average homosexuals do not breed, though they contribute to society as a whole.
It is also noted that incidents of all forms of homosexuality and schizophrenia increase during times of increased population, where elbow room is limited and people are forced to contend more with loss of privacy and individual control.
Schizophrenia has so many aspects the psychiatrists still do not understand it well, though they know it arises from a chemical imbalance in the brain, which usually shows up within the teens and 20s. People over 30 without any preexisting signs of schizophrenia rarely, if ever, develop it.
Uses in evolution? A wild card, I would think. Some very creative people have been schizophrenics. It is suspected in some circles that Joan of Ark was an active schizophrenic. Some people think schizophrenia might be the breakdown of all of a human’s normal separation of the Id, Ego and Superego. In the multiple personality stage, it is suspected that severe life experiences causes the self defensive compartmentalizing of various aspects of the personalities to allow the person to function, defend his or herself and breed. (Three faces of Eve, who currently has 21 documented personalities.)
It has been documented that if the connective tissue between the two hemispheres of a brain is severed, that something like two personalities can emerge with previously unlearned functions, like writing with both hands, accompanying them. This has led to a close investigation because when the two hemispheres are joined, they trade information and create one personality. Sever them, and they seem to develop two, with one being weaker and diffused. Current operations for severe neural disorders require removing 1 hemisphere, and the person survives, personality basically intact, though often with some control problems to over come, like a weakness in the limbs on the removed hemisphere’s control side or some lapses in speech or memory.
Schizophrenia could also be a form of population control for true schizophrenics, unless watched over, often die for various reasons, can go wild and kill people, become sociopathic, reclusive and might never breed, and, depending on the level of dementia, actually contribute great things to society. Certain forms can be controlled by medication, but they still tend to be often ‘different’ from normal people.
Think about the many prophets in the past who claim to have heard voices and to whom people listened, either meeting ruin in the long run or success, along with all of those other ancient mystics who professed to talk to the gods or the dead (excluding probably 90% who were absolute fakes, putting on a deliberate act). They might have been schizophrenic to some degree.
How many rulers were paranoid schizophrenics? That could lead to some real bloody battles. Some of the famous English Kings certainly seemed a bit paranoid schizophrenic.
But, lastly, it has been observed that when population pressures are low and communities more spread out, individual freedoms more available, that the incidents of schizophrenia decrease sharply. I would say that there are more schizophrenics in New York City, with it’s jammed up population in the million or so than in Road Kill, Texas where only 20,000 people live.
China, with it’s ever changing political oppression, social climate, high population and strict laws, probably has more schizophrenics than average nations. Then again, if the average Chinese person has limited education and exposure to other outside sources, might he not be ‘smart’ enough to develop schizophrenia because he has always lived with that society, experiencing nothing better? Food for thought.
Whew! Strained my brain on this diatrib. Sorry for the length.