Biological explanation for schizophrenia

Genetics- genes consist of DNA stands. DNA produces “instructions” for general physical features (e.g. eye colour, height) and also specific physical features(e.g. neurotransmitter levels and size of brain structure), which can consequently impact on physiological features such as intelligence or mental disorder

Suggests that schizophrenia is inherited and results from a biological process driven by the activity of certain genes, such as for brain structure development and neurotransmitter levels.

There is no one "schizophrenia gene", however a collection of gene locations have been located that are associated with a higher risk of developing schizophrenia. This means schizophrenia is thought to be a polygenetic disorder.

Gottesman(1991)- one of the family study which can confirm that risk of schizophrenia increases in line with genetic similarity to a relative with the disorder.

• Reviewed cases of schizophrenia in families

• Concordance rate for MZ twins: 48%

• Concordance rate for DZ twins:17%

• This suggests that schizophrenia has a genetic aspect as there are a large difference between the 2 sets of twins, but not 100% so not complete explanation

Tienari (2004) Studied the biological children of schizophrenic mothers who had been adopted(Finnish).

• 5.8% of children adopted into psychologically heathy families developed schizophrenia

• 36.8% of children raised in dysfunctional families developed schizophrenia

• As the risk for both groups is far above the 1% risk level of the general population this suggests SZ has a genetic basis, however difference between groups also suggest a role to play for psychological factors, suggesting that it is not only biological

Neural correlates for schizophrenia

Neural Correlates are the variations in neural structure and bio chemistry that are correlated with an increased risk of developing schizophrenia.

• The dopamine hypothesis suggest that symptoms of schizophrenia are associated with too much or an imbalance of the dopamine neurotransmitter across the brain

• The exact mechanism is not certain, however excessive amounts of dopamine (hyperdopaminergia) in speech centres like Bocas area may lead to auditory hallucinations.

• Lower levels (hypodopaminergia) in areas like the frontal cortex are thought to lead to negative symptoms like avolition or speech poverty.