A01
Interactionist approach
A way of explaining the development of behaviour by many factors including biological and
psychological ones
These factors interact and cannot be studied in isolation/separately
Diathesis stress model - is a way to present an interactionist approach
Underlying genetic vulnerability or predisposition but needs to be an environmental trigger
eg trauma or abuse to cause the onset/development of schizophrenia
In early versions of the diathesis-stress model, vulnerability was genetic and triggers were
psychological
Nowdays, both genes and trauma are seen as diatheses, and stress can be psychological or
biological in nature
Diathesis = vulnerability
Stress = negative experience
Both necessary to develop the disorder
Meehl’s model - 1962
Original diathesis-stress model said diathesis was entirely genetic, due to single
“schizogene”.
Led to idea of biologically based schizotypic personality, one characteristic of which is
sensitivity to stress
According to Meehl, if a person does not have the schizogene then no amount of stress
would lead to schizophrenia
But schizophrenogenic mother could result in schizophrenia
Modern understanding of diathesis
Clear now that many genes each appear to increase genetic vulnerability only slightly, there
is no single “schizogene” (Ripke et al)
Modern views suggest a range of factors beyond genetic, such as trauma (Ingram and Luxton
2005) - so trauma becomes the diathesis rather than the stressor
Read et al (2001) propped a neurodevelopmental model in which early trauma alters the
developing brain. Eg - hypothalamic-pituitary-adrenal system can become overactive,
making a person much more vulnerable to later stress
Genes are aetiologcally heterogeneous which means they play out differently in different
people
Modern understanding of stress
In original diathesis-stress model, stress was seen as psychological in nature
The modern definition of the stress includes anything that risks triggering schizophrenia
(Houston et al 2008)
Recent research concerned risk of schizophrenia with use of cannabis, THC rich (Di Forti et
al) - x7 more likely. May be because cannabis interferes with dopamine system. But most
people who smoke cannabis do not develop schizophrenia presumably because they lack the
requisite vulnerability factors
Treatment according to interactionist model
Interactionist model acknowledges both biological and psychological factors, therefore is
compatible with both biological and psychological treatments
Combines antipsychotic medication and psychological therapies, most commonly CBT
Interactionist approach
A way of explaining the development of behaviour by many factors including biological and
psychological ones
These factors interact and cannot be studied in isolation/separately
Diathesis stress model - is a way to present an interactionist approach
Underlying genetic vulnerability or predisposition but needs to be an environmental trigger
eg trauma or abuse to cause the onset/development of schizophrenia
In early versions of the diathesis-stress model, vulnerability was genetic and triggers were
psychological
Nowdays, both genes and trauma are seen as diatheses, and stress can be psychological or
biological in nature
Diathesis = vulnerability
Stress = negative experience
Both necessary to develop the disorder
Meehl’s model - 1962
Original diathesis-stress model said diathesis was entirely genetic, due to single
“schizogene”.
Led to idea of biologically based schizotypic personality, one characteristic of which is
sensitivity to stress
According to Meehl, if a person does not have the schizogene then no amount of stress
would lead to schizophrenia
But schizophrenogenic mother could result in schizophrenia
Modern understanding of diathesis
Clear now that many genes each appear to increase genetic vulnerability only slightly, there
is no single “schizogene” (Ripke et al)
Modern views suggest a range of factors beyond genetic, such as trauma (Ingram and Luxton
2005) - so trauma becomes the diathesis rather than the stressor
Read et al (2001) propped a neurodevelopmental model in which early trauma alters the
developing brain. Eg - hypothalamic-pituitary-adrenal system can become overactive,
making a person much more vulnerable to later stress
Genes are aetiologcally heterogeneous which means they play out differently in different
people
Modern understanding of stress
In original diathesis-stress model, stress was seen as psychological in nature
The modern definition of the stress includes anything that risks triggering schizophrenia
(Houston et al 2008)
Recent research concerned risk of schizophrenia with use of cannabis, THC rich (Di Forti et
al) - x7 more likely. May be because cannabis interferes with dopamine system. But most
people who smoke cannabis do not develop schizophrenia presumably because they lack the
requisite vulnerability factors
Treatment according to interactionist model
Interactionist model acknowledges both biological and psychological factors, therefore is
compatible with both biological and psychological treatments
Combines antipsychotic medication and psychological therapies, most commonly CBT
