One Other Biological Explanation
Schizophrenia as a Heritable Condition:
The inheritability of schizophrenia is 79% - suggesting a large role of genetic factors in
determining the disorder.
Identify responsible genes that are present in family members who have been diagnosed with the
disorder.
Jessica Wright 2014 indicated that as many as 700 genes have been linked to schizophrenia and
by now it may be in the 1000s.
Gene Mutations: Candidate Genes:
The DNA code in one or more gene may The COMPT gene:
spontaneously mutate. Linked between schizophrenia and
These changes may be the result from an DiGeorge Syndrome which may be due
environmental factor or an error during to the deletion of the COMPT gene.
cell division, such as deletion or duplication Provides instructions for the creation
of a strand of DNA. of an enzyme which breaks down
neurotransmitters such as dopamine in
the prefrontal cortex.
Diathesis-stress Model: Deletion would mean dopamine levels
Genes create a vulnerability for are poorly regulated resulting in
schizophrenia rather than causing it. schizophrenic symptoms.
Diathesis - possessing schizophrenic genes The DISC1 gene:
but the condition is only triggered by other Abnormality in this gene means people
biological or environmental factors. are 1.4 more times likely to develop
Stress was seen as psychological in nature schizophrenia.
like harsh parenting - ‘refrigerator Creation of GABA, a neurotransmitter
mother’. which regulates other
Now it includes anything that risks neurotransmitters such as glutamate
triggering schizophrenia. and dopamine in the limbic system.
Evaluation
Strength:
Irving Gottesman 1991 analysed the concordance rates for people with different genetic
similarity - there was a clear relationship between genetic similarity and increase in related
individuals both having schizophrenia.
Concordance rate for MZ twins was 42% and 9% in DZ twins.
Shows while schizophrenia is not entirely genetic, biology certainly plays a part - concordance
rate is higher for MZ twins than DZ.
Schizophrenia as a Heritable Condition:
The inheritability of schizophrenia is 79% - suggesting a large role of genetic factors in
determining the disorder.
Identify responsible genes that are present in family members who have been diagnosed with the
disorder.
Jessica Wright 2014 indicated that as many as 700 genes have been linked to schizophrenia and
by now it may be in the 1000s.
Gene Mutations: Candidate Genes:
The DNA code in one or more gene may The COMPT gene:
spontaneously mutate. Linked between schizophrenia and
These changes may be the result from an DiGeorge Syndrome which may be due
environmental factor or an error during to the deletion of the COMPT gene.
cell division, such as deletion or duplication Provides instructions for the creation
of a strand of DNA. of an enzyme which breaks down
neurotransmitters such as dopamine in
the prefrontal cortex.
Diathesis-stress Model: Deletion would mean dopamine levels
Genes create a vulnerability for are poorly regulated resulting in
schizophrenia rather than causing it. schizophrenic symptoms.
Diathesis - possessing schizophrenic genes The DISC1 gene:
but the condition is only triggered by other Abnormality in this gene means people
biological or environmental factors. are 1.4 more times likely to develop
Stress was seen as psychological in nature schizophrenia.
like harsh parenting - ‘refrigerator Creation of GABA, a neurotransmitter
mother’. which regulates other
Now it includes anything that risks neurotransmitters such as glutamate
triggering schizophrenia. and dopamine in the limbic system.
Evaluation
Strength:
Irving Gottesman 1991 analysed the concordance rates for people with different genetic
similarity - there was a clear relationship between genetic similarity and increase in related
individuals both having schizophrenia.
Concordance rate for MZ twins was 42% and 9% in DZ twins.
Shows while schizophrenia is not entirely genetic, biology certainly plays a part - concordance
rate is higher for MZ twins than DZ.
