Of (Schizophrenic) Mice and Man – Genes Don’t Tell All

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Do animals suffer from mental illnesses?

Scientists from the California Institute of Technology in Pasadena (Caltech), have found that mice that lack a certain gene display schizophrenic behavior similar to those of humans.These animals are unable to produce sufficient amounts of a protein called Densin which is known to be related to schizophrenia in humans. They displayed higher levels of stress and anxiety and poor short-term memory.

It is now well established that our body is really just a bag of molecules interacting in a highly organized manner – I have pointed to this in Consciousness & Free Will – They Are Just Illusions and other  posts. Most of these molecules are proteins, and are responsible for defining what we are – our structure and function – from moving a muscle to thinking about it to going gaga.

We also know that genes in our DNA molecule determine what kind of protein molecules we can make. Many of us would sigh and resign to the fact that, well, it’s in my DNA – nothing I can do about it.

Well, that’s not true at all. Having the gene is one thing; expressing – making a molecule with it – is another. There are many regulatory molecules inside the nucleus that repress or activate individual gene expression. For example, in a pair of identical twins, one may have schizophrenia and the other has bipolar syndromes or none at all, meaning the same genes don’t necessarily produce identical persons. This secondary control of our genes is loosely called epigenetics.  It could be caused by regulator genes, or many environmental factors, and could likely be more important than a person’s actual DNA in determining his constitution. This implies the huge potential for learning and training for individuals.

There is now evidence that some epigenetic processes may even be inheritable. Experimenting with mice, researchers in ETH Zurich have demonstrated that mice that have been exposed to chronic stress when young grow up to not only exhibit anti-social and other abnormal behaviors, but that their offspring acquire the same symptoms. In humans, it is well known that traumatic experience or chronic severe stress during childhood can result in personality disorder and bipolar depression as adults. And the ETH Zurich researchers believe that the inheritance model in mice here could apply to humans and are planning further experiments.

But other experiments are pointing to something even more amazing, something that might someday lead to our discovering the genetic basis of human creativity.

The relationship between creativity and mental illness has been quite reliably established (see my post, Winston’s Black Dog and Vincent’s Left Ear – Creativity & Mental Illness). Furthermore, scientists in Australia’s University of Queensland’s Queensland Brain Institute have determined that there is a network of about 4000 genes in our DNA that are involved in various kinds of mental disorders, including schizophrenia, chronic depression, even autism. They speculate that symptoms such as anxiety, loss of short term memory etc. may not be reliable diagnoses of various mental illnesses; but rather many mental disorders are probably related, depending instead on epigenetic expression and the relative quantities of certain molecules in an individual.

The New York Times reported last month on an experiment published in the Lancet, involving over 60,000 people worldwide that there are stretches of chromosome with aberrations which underlie various mental disorders like schizophrenia, bipolar disorder, autism, major depression and attention deficit hyperactivity disorder (ADHD). These disorders may have different behavioral patterns but they share several genetic glitches that “can nudge the brain along a path to mental illness. Which disease, if any, develops is thought to depend on other genetic or environmental factors”. See  Same Genetic Basis Found in 5 Types of Mental Disorders.

There’s more evidence still. The Australian researchers at Queensland Brain Institute also reported molecular networks in the brains of mental health patients. This paper  is the result of a global and comprehensive review of current data linking genes to mental disorders :

Although our analysis shows that the many genetic variations with the four disorders [ADHD, autism, schizophrenia and X-linked intellectual disability] can affect the same molecular pathways and biological functions, including how nerve cells connect (synapses), there are patterns of variation that define significant differences between disorders” [my emphasis]

The important implication of this study is that mental illnesses can in future be accurately diagnosed, from a person’s DNA or the presence of certain molecules, possibly before symptoms occur. The current reliance on behavioral descriptions is highly imprecise and subjective.

So my question is: If the molecular pathways of mental illnesses can be traced to their genetic origins, can our biological understanding of creativity be far behind?

 

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