Description: Are there forms of psychopathology among non-human animals (perhaps)? What about schizophrenia (perhaps not)? What is it about schizophrenia that may make it a uniquely human disorder?
Sources: Scientific American: Why Don’t Animals Get Schizophrenia (and How Come We Do)?
Date: March 25, 2015
Photo Credit: Jessie Wilcox Smith (http://en.wikipedia.org/wiki/Jessie_Willcox_Smith)
Laurel Braitman writes in her book Animal Madness (2014) that “…every animal with a mind has the capacity to lose hold of it from time to time.” Some dogs and zoo polar bears have been put on Prozac, birds obsess, horses can become seriously compulsive and dolphins and whales in captivity can self-mutilate. However, it seems that only humans show symptoms of schizophrenia. A question to ponder is why is it that a genetically linked disorder that can be so devastating be so prevalent (1% of the population) while being so counter adaptive?
One suggestion might be that the incidence of schizophrenia is a cost or consequence of our big brain and of the higher, complex cognition it affords us. Joel Dudley and his colleagues suggest that there are a number of “human accelerated regions” (HARS) in the brain – areas that have developed rapidly, evolutionarily speaking, and which distance us from other primates like chimpanzees with whom we otherwise share a lot of genetic material. Dudley’s research looks at whether schizophrenia related genes sit near HARS genes along the human genome and it turns out that they do just that. This suggests that those genes may provide some specific adaptive advantages despite the downside of their link to schizophrenia. Specifically it seems that genes related to restraint and related frontal lobe functions, when they malfunction may also be tied to schizophrenia symptoms like hallucinations and delusions. Likewise with complex social thought, when functions associated with complex thought go awry complex malfunctions result. Genes associated with aspects of extraordinary cognitive skills are also associated with autism.
So perhaps the higher or more complex forms of thinking that may be unique to humans also come with a unique price.
Questions for Discussion:
- Explain how human accelerated brain regions may be related to human-unique disorder patters such as schizophrenia and autism.
- What might some implications of this suggestion be for treatment research and planning?
- How might the onset of hallucinations be related to the restraint function of the frontal lobes of the human brain?
References (Read Further):
Braitman, Laurel (2014) Animal Madness, Simon and Schuster, New York.
Joel Dudley’s Lab webpage (with references) http://dudleylab.org/
Clark, T.K, et al (2015) Common polygenic risk for autism spectrum disorder (ASD) is associated with cognitive ability in the general population, Molecular Psychiatry, (10 March, 2015), 1-7.