WEEK 5 - 2: Nature and Nurture

Developmental psychopathology

  • different approaches

    • clinical diagnostic approach

      • by someone profesionally trained

      • consider frequency of symptoms before diagnosis

    • emperical quantitative approach

      • continuous scale used to measure mental health problems

      • can still used a clinical cutoff

      • disorders at extreme ends of the distribution

  • classification

    • internalising - feelings, emotions (anxiety)

    • externalising - bhv (attentional problems)

Psychopathology in children and youth

  • major public health issue

  • 10-25% depending on categories of population

  • have early onset - 75% before 25y

  • chronic/ long lasting - 60% in young people, 22-46%

  • a lot of work going to early intervention

Study of nature and nurture

  • origins and causes of psychopathologies

  • why things overlap?

  • genetics involved?

  • interactions with environment?

  • predictions and treatments/ preventions - new drug targets and interventions found/ created

  • risk reduction interventions

Twin design

  • phenotypic variation (P) : observed variable

    • heritability (A, h2): influences of genetic factors

    • Shared environment (C, c2): any environmental influences that contribute to the similarity between co-twins

    • non-shared environment(E, e2): any aspect of environmental influences that makes twins different from each other

  • P = h2 + c2 + e2

  • heritability (A) = 2(rMZ - rDZ)

  • Shared environment (C) = rMZ - h2

  • Non-Shared environment (E) = 1 - rMZ

  • ACE Model

    • structure approaching model used

    • presented as a path diagram

    • A - additive

    • C - common environmental effects

    • E - non-shared environmental effects

Sub-types of antisocial bhv

  • children w/ onset early antisocial bhv

  • group w/ callous-unemotiona traits (CU)

  • group w/out CU

  • results

    • more genetically influenced

Co-occurence/ Comorbidity

  • co-occurence of two different disorders/ disabilities

  • both can be observed at the same time:

    • depression and anxiety

    • ADHD with language problems

    • reading disability with mathematics disability

ACE Models

  • separate estimation of genetic A and environmental C-shared, E-nonshared enfluences

  • assumptions - equal environments

Genetic Variation

  • what contributed to individual differences and bhvl traits?

  • humane genome is built with 3 billion base pairs

  • 20-25%

  • more tha 99% od the DNA sequence is the same for everybody

  • only 1% of the DNA sequence is variable

Pathologies are polygenic traits

  • psychopathologies are influenced by polygenic traits - like skin colour

  • each genetic variant is additive to the others: more specific genetic variants (alleles) - higher risk of psychopathology

robot