Biological explanations for schizophrenia

• The genetic basis of schizophrenia - Family studies confirmed that the risk of schizophrenia increases with genetic similarity to relatives with the disorder. Gottesman (1991) conducted a large scale study looking at family concordance rates.
• Candidate genes are genes that are associated with a particular disease or condition.
• Schizophrenia was found to be polygenic (controlled by many genes) where the genes code for neurotransmitters eg. dopamine
• Ripke et al (2014) conducted a meta-analysis from genome studies looking at the genetic makeup of 37,000 people with a diagnosis of shizophrenia and compared it to 113,000 controls. Found that schizophrenia is also aetiologically heterogeneous (controlled by many factors).
• The role of mutation - Mutation in parental DNA which can be caused by radiation, poison. etc.
• Neural correlates are the brain activity that occurs when a person is performing a task.
• Neural correlates of schizophrenia - the original dopamine hypothesis suggests that schizophrenia is caused by a deficiency of dopamine in the brain.
• The original dopamine hypothesis: Parkinsons disease is a condition associated with low DA levels therefore, schizophrenia is due to high DA levels.
• High levels of dopamine in the subcortex and brocas area = original dopamine hypothesis
• Low levels of dopamine in the prefrontal cortex = updated dopamine hypothesis
• Brown(2002) = Correlation between parental age and development of Sz.
• Original and dopamine hypothesis explains positive and negative symptoms