Epigenetics of Schizophrenia
By P. J. Gebicke-Haerter
Positive and negative symptoms: apathy, lack of emotion, poor or non-
existent social functioning, hallucinations, delusions, and racing thoughts to
name a few.
Cognitive symptoms: disorganized thoughts, difficulties concentrating or
following instructions, difficulties completing tasks and memory problems
The genetic origin of the disorder
Uncertainty as to schizophrenia’s heritability
o Very slight identifiable differences in DNA sequencing
o Of the 80%-90% heritability that is attributed to major psychiatric
illnesses, only 2% of that can be attributed to the differences in
sequences of the DNA
o Epigenetic differences: altering of gene function without altering the
Monozygotic twin studies
Whether or not someone will be ill is a result of predisposition to illness, and this can
be a result of changes in genetic hardware or software.
1. Differences in DNA sequences
We are talking about changes in genetic hardware
o Change occurred in the coding part of the gene, when different amino
acids are sequenced together to form a protein with a specific function
o Qualitative changes.
2. Epigenetic differences
We are focusing on the genetic software,
Mutations that take place in the non-coding part of a gene
Changes in genes can occur later in life as well by substances, or x-rays for example.
A biological mutation can result from an external stimulus.
Models of developmental psychopathology suggest that the impact of an
event is dependent on the time, intensity, and context of the event
It is during early life
Brain regions involved in schizophrenia Dopaminergic pathways, serotonin pathways, certain G-proteins among
Common gene studies are not enriched enough to examine the differences
that are present in the etiology of schizophrenia
Through meta-analysis single-nucleotide polymorphism has been found in
close proximity to the major histocompatibility complex on chromosome 6
MHCs are molecules that mediate interactions of genes with the immune system.
It is these molecules that control susceptibility to illness
o Because of these findings, it was thought that schizophrenia is the