genes and schizophrenia

Mike Lieber (U28550@UICVM.BITNET)
Wed, 19 Oct 1994 08:22:54 CDT

Dave DeGusta states that standards of proof of genetic hypotheses ought to be
applied across the board. I could not agree more. He cites schizophrenia as
an example, and he couldn't have picked a better one. In 1957, Gregory Bateson
published the second in a long series of articles on the "double bind" theory
of schizophrenia entitled "Minimal requirements for a theory of schizophrenia."
He explored the evolutionary implications of paradoxical structuring of
commnicational circuitry, and he predicted that researchers should find some
enzymic imbalance, probably genetically caused, associated with at least some
forms of schizophrenic symptoms. The problem with such a discovery would be
determining whether the double bind was an outcome of the enzyme imbalance or
a trigger for its expression. Years later, NIH sponsored researchers did
indeed discover an allele whose protein caused the enzymic imbalance that
Bateson had predicted. Ironically, psychiatrists either forgot or never knew
about the prediction, and they took the discovery to be a falsification of the
double bind hypothesis. Deep thinkers.

The problem with the discovery was that further testing with patients and
control groups showed that the allele had only 50% penetrance. That is, only
half of the people with the allele showed schizophrenic symptoms. Research
seems to have stopped there. Had the penetrance been 100% or close to it,
the double bind hypothesis could have been classed as one of several possible
outcomes of (genotypic expressions of) the allele. But 50% penetrance
suggests that the double bind is a trigger. The next step of research should
have been to study the families of the patients and non-patients to determine
differences, if any, in their communication patterns. The results of that
research would have made a further step, examination of the variability in
chemical pathways involving the normal allele and the mutant allele, feasible
and necessary. The money ran out, and it never happened. Scientists love
complexity, but funding agencies are often another matter.

Mike Lieber