biological explanations

• One biological explanation for schizophrenia is family studies. This determines that a person has a higher risk of developing schizophrenia if a family member has it due to a genetic vulnerability. Gottesman found a positive correlation between genetic similarity and a higher risk of developing schizophrenia. He found that there is a concordance rate of 6% between parents, 9% between siblings and 48% between monozygotic twins.
• Candidate genes are also involved in the risk of developing schizophrenia, specifically neurotransmitters. Ripke et al conducted a large-scale study using data from genome wide studies. He studied 37,000 schizophrenics and compared it to a control group of 113,000 non schizophrenics. He concluded that there were 108 genetic variations involved in the development of schizophrenia. This therefore means schizophrenia is a polygenetic condition. 
• dopamine hypothesis - if there is excess of dopamine in certain areas of the brain, then an individual is more likely to experience positive symptoms of schizophrenia. Research found schizophrenics have higher number of d2 receptors on neurons, which leads to increased binding - can be supported through drugs studies. amphetamines = dopamine antagonists; they stimulate nerve cells containing dopamine causing synapses to be flooded. When people without schizophrenia take these, they experience positive symptoms such as hallucinations, but these go away when individual is not taking the drug.
• A03

  + strength of family studies is- adoption studies - used to determine whether families have a higher vulnerability of developing the condition as they share similar environments rather than sharing genetic material. Tienari et al conducted adoption study on children who grew up in adopted families, and whose real parents had schizophrenia. Despite living in a completely different environment to them, they still had a high risk of developing the condition. This therefore supports the idea that genetic vulnerability can put individuals at a high risk of schizophrenia
• A03

  -biologically reductionist - doesn’t consider other factors that explain schizophrenia such as environmental (through smoking cannabis), psychological ( =growing up with a schizophrenogenic mother). Gottesmans study- only a 48% concordance rate between monozygotic twins - shows that environmental factors also have a role to play in the development of schizophrenia, as mz twins share 100% of genes so should therefore have a 100% concordance rate. thus, reduces validity of this explanation as it is not comprehensive as it does not consider any other factors
• A03

  +One strength of the dopamine hypothesis is its use of scientific methods. For example, to measure dopamine, blood tests are used. These are objective meaning they are not subject to researcher bias like other, subjective methods. This therefore increases the scientific credibility of this explanation, as it develops empirical data, which therefore helps contribute to psychology as a science. Furthermore, it also reduces the effects of extraneous and confounding variables therefore increasing the internal validity of the data produced.
• A03

  -However, NOLL argues against the dopamine hypothesis. He claims that 1/3 of people taking antipsychotics do not experience a reduction in positive symptoms and people who experience hallucinations do not always have an excess of dopamine in the brain. Therefore, this reduced the reliability of the dopamine hypothesis as an explanation as it is affected by individual differences, making it a less comprehensive explanation. Thus, this means further research is needed.
• NEURAL CORRELATES

  PREFRONTAL CORTEX - involved in planning and reasoning - is often impaired in schizophrenics

  HIPPOCAMPUS -located in temporal lobe - defecits in nerve connections between hippocampus and prefrontal cortex leading to memory loss

  reduced GREY AND WHITE MATTER