A new study has found that there is not a single type of
schizophrenia, but that it consists of a group made up of eight genetically
different types of diseases.
The research, jointly conducted by the University of Granada
(Spain) and Washington University in St. Louis (US), could be an important
first step towards a better diagnosis and treatment of the disease, which
affects approximately 1 percent of world population.
Previous study has revealed that about 80 percent of the risk of
suffering from schizophrenia was hereditary. The new study has for the first
time identified the different gene networks that contribute to the existence of
eight different types of schizophrenia.
The research involved 4,196 patients diagnosed with schizophrenia
and 3,200 healthy patients participated as control group.
Igor Zwir, a researcher at the University of Granada and
co-author of the study says that, "After a decade of frustration in the field
of psychiatric genetics, we identified the manner in which the genes interact
with each other, in an orchestrated manner in the case of healthy patients, or
disorganised, as happens in the cases that lead to the different types of
In some patients with hallucinations or delirium, for instance,
scientists agree that there are different networks of genes related to their
respective symptoms, which demonstrates that specific genetic variations
interact with each other.
This genetic analysis leads to 95 percent certainty in
predicting the onset of schizophrenia.
They found, in another group, incongruent speech and disorganised
behaviour are specifically associated with a DNA variations network that leads
to a 100 percent risk of suffering schizophrenia.
Scientists divided the patients according to the type and
seriousness of positive symptoms such as different types of hallucinations or
deliriums, or negative symptoms such as lack of initiative, troubles in
organising thoughts, or lack of connection between emotion and thought.
In parallel, they classified the profiles of these symptoms into
eight qualitative types of different diseases according to the underlying
Researchers say, "Though individual genes only present weak, inconsistent
associations with schizophrenia, the interaction networks of gene groups pose a
high risk of suffering from the disease, between 70 and 100 percent, "which
makes it almost impossible that individuals with those genetic variation
networks will avoid schizophrenia."
Scientists found a total of 42 genes groups that influenced in a
variety of ways the risk of suffering schizophrenia.