Biological Explanations Of Schizophrenia

Question 1

Biological explanations

Answer 1

Emphasises the role of inherited factors and dysfunction of brain activity in the development of schizophrenia
• genetics
• dopamine (role of neurotransmitters)
• neural correlates

These explanations are inter related as if SCZ is genetic, those genes lead to biological differences such as abnormal levels of dopamine or structures of the brain

Question 2

Genetic explanation

Answer 2

Suggests SCZ runs in families and is inherited as genes are transmitted from parent to child

SCZ is thought to be a polygenic disorder: a collection of gene locations have been located that are associated with higher risk of developing SCZ

Question 3

Genetic explanation (2 evidence)

Answer 3

RIPKE - genetic analysis of 36,000 cases identified 108 genetic loci associated with the development of SCZ

GOTTESMAN - large-scale family study
• Found much higher concordance rates in MZ twins (48%) in comparison to DZ twins (17%) which suggests a strong biological component
• However if it was simply genetic in identical twins the concordance rate should be 100%

Question 4

Neural correlates (with evidence)

Answer 4

Ventricles (voids filled with cerebrospinal fluid deep within the brain) are through to provide a prtectuv cushioning effect for the brain. ENLARGED ventricles are associated with people with SCZ

JOHNSTONE - research using CT scans first identified people with SCZ as having larger than average ventricles
However this is based off of correlation research and so we cannot determine a causal relationship or the existence of a third factor

(Negative symptoms)
Ventral Striatum is thought to be involved in the anticipation of reward - abolition involves the loss of motivation

JUCKEL - found a negative correlation between activity levels and severity of overall negative symptoms

Question 5

Dopamine hypothesis

Answer 5

Suggests that symptoms are associated with an imbalance of the dopamine neurotransmitter across the brain

DAVIS+KHAN:

Positive symptoms: caused by higher activity levels in the sub context
• Excess dopamine - hyperdopaminergia - in speech centres may lead to auditory hallucinations

Negative symptoms: caused by lower levels of dopamine in pre-frontal cortex
• Lower dopamine - hypodopaminergia - in areas such as pre-frontal cortex is thought to lead to negative symptoms like avolition and speech poverty
•• Came about from observations that dopamine drugs such as L-Dopa can produce schizophrenic like symptoms in healthy individuals

LEUHT - meta analysis review of 212 studies that assessed the effectiveness of anti-psychotic drugs that work via normalising dopamine levels
• These drugs were more effective than placebos
• suggests their underlying biological components have validity otherwise the drugs would not be effective

Question 6

Evaluations

Answer 6

• Assumes SCZ is inevitable talking a biological deterministic view. This can make sufferers feel disempowered when diagnosed
Other approaches like the cognitive approach take a soft determinist approach suggesting mental processes can be managed via free will to control the disorder

• Taking a holistic explanation may be more valid as it would include the diathesis stress model

• Explainign SCZ at a basic cellular levels has the advantage of the scientific principles of parismony. Studies are highly controlled and provide empirical evidence for the influence of biological components