Why don't animals get schizophrenia? (And how come we do)?
Patricia Thompson stashed this in Random Tidbits
Put another way, with complicated, highly social human thought—and the complicated genetics at the root of higher cognition—perhaps there’s just more that can go wrong: complex function begets complex malfunction.
Dudley is careful not to exaggerate the evolutionary implications of his work. “It is important to note that our study was not specifically designed to evaluate an "evolutionary trade-off,” he says, “but our findings support the hypothesis that evolution of our advanced cognitive abilities may have come at a cost—a predisposition to schizophrenia.” He also acknowledges that the new work didn’t identify any “smoking gun genes” and that schizophrenia genetics is profoundly complex. Still, he feels that evolutionary genetic analysis can help identify the most relevant genes and pathologic mechanisms at play in schizophrenia, and possibly other mental illnesses that preferentially affect humans as well—specifically neurodevelopmental disorders related to higher-cognition and GABA activity, including autism and ADHD.
In fact, a new study published in Molecular Psychiatry reports a link between gene variants associated with autism spectrum disorder and better cognitive function in people without the disorder. The findings may help explain why those with autism sometimes exhibit extraordinary skill at certain cognitive abilities. They also support Dudley’s speculation that higher cognition might have come at a price. As we broke away from our primate cousins our genomes—HARs especially—hastily evolved, granting us an increasing cache of abilities that other species lack. In doing so, they may have left our brains prone to occasional complex dysfunction—but also capable of biomedical research aimed at one day, hopefully, curing the ailing brain. As Dudley and others untangle the genetic underpinnings of schizophrenia and other mental illnesses in search of improved diagnosis and treatment, at least our pugs, poodles and pot-bellied pigs seem to be psychosis free.
Intuitively it makes sense that with much more circuitry, much more can go wrong.