Genetic basis

• Genetics

  DNA produces instructions for general features adn specific physical features

  Thee any impact psychological features

  genes are inherited
• family studies

  confirmed the risk of SZ increases in line with genetic similarity

  someone with an aunt wit SZ has a 2% chance of developing it, this increases to 48% if they are an identical twin
• candidate genes

  SZ is seen to be polygenic, the most likely genes are those that code for neurotransmitters

  the genetic makeup of 37000 SZ patients compared to 113000 controls showed 108 separate genetic variation were associated with an increased risk of SZ
• mutation

  SZ can have a genetic origin even in the absence of a family history of the disorder

  a mutation in parental DNA
• A strength of the genetic explanation is a strong evidence base

  Family studies show that risk increases with genetic similarity to a family member with SZ.

  Adoption studies show that biological children of parents with SZ have an increased risk even if they grow up in an adoptive family

  This shows that some people are more vulnerable to SZ as a result of her genetic make up
• A limitation is, there is clear evidence to show the environmental factors also increase the risk

  Biological risk factors include complications with birth and smoking cannabis in teenagers

  Psychological risk factors include childhood trauma which leaves people more vulnerable to adult mental health problems

  this suggests genetic factors can’t provide a full explanation