Human and Animal Development Flashcards

Question

: Genetics of Schizophrenia

Answer 1

* Specific clinically defined category of neurodiversity * Long-term condition that involves psychosis * Difficulty in distinguishing own thoughts from reality * Long term debate about whether this is genetically inherited (nature) or induced by the environment (nurture) Case study: Genetics of Schizophrenia * Historically, (up to 1970s) – thought to be related to upbringing of children * Early studies in 1950s -1970s identified that it ran in families - a possible genetic influence? * Twin studies demonstrated a high degree of heritability Case study: Genetics of Schizophrenia * Historically, (up to 1970s) – thought to be related to upbringing of children * Early studies in 1950s -1970s identified that it ran in families - a possible genetic influence? * Twin studies demonstrated a high degree of heritability * Concept of “genetic susceptibility” * Other factors affect it, but only individuals that are genetically susceptible Case study: Genetics of Schizophrenia * 2017 Danish twins study (Hilker et al 2017) * Danish Twin register – started in 1954 and includes twins born from 1870 onwards * Complete records for all Danish-born twins born from 1968 * Danish Psychiatric Central Research Register – all pyschiatric admissions since 1969 * 31,524 twin pairs But other factors are involved… * Includes upbringing…but only if genetically susceptible * More schizophrenic individuals born in winter rather than summer….linked to influenza epidemics * Infectious agents – the parasite Toxoplasma gondii * Development errors in the brain of the brain (non-genetic) * Dietary…deficiency of essential fatty acids * So both nature and nurture contribute…and its com

Answer 2

* Need a Standardised measure of intelligence * Intelligence Quotient (IQ) * But does not measure all forms of intelligence * However, a strong correlation between IQ and success at school Case study: Genetics of intelligence * Twin studies show a heritability of around 50% * Moderate influence of genetics Case study: Genetics of intelligence * Twin studies show a heritability of around 50% * Moderate influence of genetics * 25% comes from the shared environment for the twins * 25% from their unique environment Case study: Genetics of intelligence * Twin studies show a heritability of around 50% * Moderate influence of genetics * 25% comes from the shared environment for the twins * 25% from their unique environment * Heritability increases with age (less than 40% at age 9 but as high as 80% beyond age 20) * Suggests that the environmental effects are more significant earlier in life Case study: Genetics of intelligence * Twin studies show a heritability of around 50% * Moderate influence of genetics * 25% comes from the shared environment for the twins * 25% from their unique environment * Heritability increases with age (less than 40% at age 9 but as high as 80% beyond age 20) * Suggests that the environmental effects are more significant earlier in life * So both nature and nurture contribute…and its complex