biological explanations for Schizophrenia

Outline biological explanations for Schizophrenia

A01

It has been shown that schizophrenia has a tendency to run in families, with those being genetically related being more likely to develop the disorder than those related by marriage. A study conducted on twins by Joseph (2004) calculated that the concordance rate for mz twin is 40.4% compared to 7.4% for dz twins.

outline part 2

• An alternative explanation is the dopamine hypothesis. Dopamine is a neurotransmitter, when in excess seemingly causes the positive symptoms of schizophrenia. Davis and Kahn proposed a revised dopamine hypothesis in which they suggested that the positive symptoms of schizophrenia are due to an excess of dopamine in subcortical regions of the brain. Conversely, they suggested that the negative symptoms are due to a lack of dopamine in the mesolimbic pathway. Deficits to the hippocampus and its links to regions of the brain like the prefrontal cortex have been implicated in the onset of schizophrenia, with Gotto and Grace (2008) finding that hippocampal dysfunction influences a reduction in dopamine release. This in turn affects processing in the PFC, causing the cognitive symptoms of the disorder.

Evaluate biological explanations

AO3 1. The difference in concordance found by Joseph may be due to mz twins being treated more similarly. The effects of the environment are hard to remove from such studies, its as a result hard to distinguish the cause of the high concordance rate- genes, or the environment.

2. Attempts to remove the effects of the environment come in the form of adoption studies. But for these to be acceptable, an assumption must be made that adoptees have not been selectively placed. Kringlen (1987) and Joseph (2004) found that prospective parents often receive information about the child prior to adoption.

AO3

3. Noll (2009), however, claims there is evidence against the revised dopamine hypothesis. He argues that antipsychotics do not alleviate positive symptoms in a third of patients, as these drugs aim to normalise dopamine levels, their failure brings the link between dopamine and positive symptoms into question.

4. The Neural explanations can allow for early detection and therefore treatment.

Addington et al (2015) completed a longitudinal study in which brain scans were done, this suggests that brain tissue can be predicted, allowing patients to be treated before symptoms develop.