Week 4 - Prenatal and postnatal exposures - BB(3)

Page 1: Introduction

  • Focus on prenatal and postnatal environmental exposures.

  • Presented by Dr. Alyson Dodd.

Page 2: Recap Last Week

  • Discussed aspects of genes:

    • Genetic predisposition

      • Heritability, genetic variants, and polygenic risk scores.

    • Pleiotropy:

      • Overlap in disorders.

    • Similarities in adult and child psychopathology:

      • Earliest manifestations and prediction of multiple disorders by PRS.

  • Emphasis on small effects in complex multifactorial disorders.

Page 3: Lecture Structure

  • Key Topics to be covered:

    • Importance of early development.

    • Examples of environmental risk factors:

      • Maternal infection

      • Alcohol exposure

      • Maternal distress

    • Concept of cumulative risk.

Page 4: Learning Outcomes

  • Understand how environmental challenges affect early development (prenatal & infancy).

  • Critically evaluate the relationship between prenatal/postnatal exposures and psychopathology.

Page 5: Missing Heritability

  • Discrepancies between twin and genome-wide association studies (GWA):

    • Potential reasons include:

      • Overestimation of genetic contributions.

      • Smaller, less noticeable effects not detected.

      • Rarer genetic variants might be overlooked.

  • Importance of environmental factors, particularly in infancy and childhood (Joseph, 2012).

Page 6: Early Environmental Factors

  • Prenatal influences (before birth):

    • Womb as the initial environment.

  • Importance of the infancy stage and its critical developmental impact.

Page 7: Critical Nature of Early Development

  • Plasticity in development most active during early stages.

  • Key developmental processes include:

    • Proliferation, pruning, myelination.

  • Cortical specialization:

    • Role of expectable stimuli and experiences in critical/sensitive periods (Nelson & Garbard-Durnam, 2021).

Page 8: Developmental Insults

  • Definition of developmental 'insults' or hazards:

    • Violations of expected environments (absence or presence).

  • Enhanced impacts during critical periods:

    • Molecular brakes help maintain structure and function.

    • Applies to both typical and atypical development (Nelson & Garbard-Durnam, 2021).

Page 9: Vulnerability of Developing Brain

  • Blood-brain barrier: not fully formed in the developing brain.

  • Vulnerability of growing cells.

  • Limited ability to break down toxins (Lanphear, 2015; Nelson & Garbard-Durnam, 2021).

Page 10: Impact of Toxins

  • Different toxins affect various developmental processes.

  • Windows of vulnerability exist, but not fully understood.

  • Complex and prolonged exposures can yield more severe negative effects (Lanphear, 2015; Nelson & Garbard-Durnam, 2021).

Page 11: Prenatal Infection and Psychopathology

  • Focus on pathogens, including viruses.

  • Increased interest in COVID-19 related outcomes.

  • Mechanisms linking prenatal infections to offspring psychopathology include:

    • Epidemiologic data from pandemics.

    • Biomarkers from maternal serum.

    • Hospital records and self-reports, all of which have limitations (Cheslack-Postava & Brown, 2022; Suleri et al., 2023).

Page 12: Mechanisms of Infection Exposure

  • Direct effects if infections cross the placenta, damaging the developing brain.

  • Indirect effects include:

    • Perinatal transmission and maternal immune activation.

    • Inflammatory cascades disrupting brain development.

    • Concept of a two-hit model that primes the immune system (based on animal models; Suleri et al., 2023).

Page 13: Infection Exposure and Psychopathology

  • Insights from a longitudinal population-based cohort study covering various infections during pregnancy.

  • Controlled for factors such as polygenic risk and early environmental influences.

  • Findings indicate that greater exposure correlates with increased psychopathology (total, internalizing, externalizing) across all trimesters (Suleri et al., 2023).

Page 14: Neurodevelopmental Disorders

  • Retrospective cohort studies in US hospitals show that maternal COVID-19 exposure links to higher rates of neurodevelopmental disorders in offspring.

  • Notable areas affected include:

    • Motor function, speech, and language during the first 12 months (Edlow et al., 2022).

Page 15: Schizophrenia Risk

  • Review of studies identifying increased risks for offspring exposed to:

    • Influenza, Toxoplasma gondii, and bacterial infections.

  • Less evidence found for herpes virus impacts.

  • Risk factors may interact with protective factors (Cheslack-Postava & Brown, 2022).

Page 16: Alcohol Exposure and Psychopathology

  • Alcohol is a teratogen that can cross the placenta.

  • Linked to Fetal Alcohol Spectrum Disorder (FASD) and subsequent developmental milestones.

  • Statistics indicate that 9.8% of alcohol use in pregnancy in the UK, with a 41.3% prevalence of alcohol exposure in general populations (Popova et al., 2017; Subramoney et al., 2018).

Page 17: Fetal Alcohol Spectrum Disorder (FASD)

  • Key characteristics include:

    • Distinctive facial dysmorphia.

    • Various health problems, intellectual disabilities, and delays in language, motor skills, and cognitive functions.

    • Associated behaviors include attention issues, hyperactivity, and aggression.

Page 18: Alcohol and Developmental Outcomes

  • Multiple detrimental outcomes from prenatal alcohol exposure identified through studies:

    • Dose-response relationship.

    • Developmental cascades observed, with postnatal environment potentially masking or exacerbating effects (Subramoney et al., 2018).

Page 19: Alcohol's Broader Impacts

  • Studies suggest even lower levels of alcohol exposure (not leading to FAS) are linked to increased risks of:

    • General problems, anxiety, depression, and conduct disorders.

  • Less evidence connecting prenatal alcohol exposure to internalizing or emotional problems (Easey et al., 2019).

Page 20: Early Exposure to Parent Distress

  • Interaction of genetic and environmental risk factors in development.

  • Pregnancy exposure leads to:

    • Biological pathways regarding the HPA axis regulation and prenatal stress hormones.

  • Childhood exposure involves environmental factors such as parenting.

  • Not designating intergenerational transmission as deterministic (Aktar et al., 2019; Bailey et al., 2021).

Page 21: Maternal Distress and Psychopathology

  • Longitudinal studies show strong links between maternal depression/stress during pregnancy and increased risk of psychopathology in adolescence.

  • Patterns of exposure leading to either stability at low levels or increased psychopathology.

Page 22: Prenatal Stress and Schizophrenia Disruption

  • Evidence indicates prenatal maternal stress heightens schizophrenia spectrum disorder risks.

  • Additional factors during pregnancy and potential postnatal insults contribute to risk cascades (Lipner et al., 2019).

Page 23: Cumulative Effects on General Psychopathology

  • Adverse cumulative prenatal exposures lead to dimensional psychopathology symptom development.

  • No clear association with childhood psychopathology linked to:

    • Birth method, preterm birth, substance use, or post-pregnancy substance use (Roffman et al., 2021).

Page 24: Cumulative Effects Insight

  • Contrasts with findings where cumulative effects of prenatal exposures (like unplanned pregnancy and substance use) are associated with dimensional psychopathology in childhood.

  • Note that none alone significantly increased risk (Roffman et al., 2021).

Page 25: Additional Considerations

  • Areas not covered in depth:

    • Medications (e.g., valproate)

    • Birth complications

    • Parental age, birth weight, timing of birth, diet, and potential accidents/injuries.

Page 26: Summary

  • Emphasizes the importance of both prenatal and postnatal environments in relation to psychopathology risk factors.

  • Highlights known (e.g., FASD) and potential correlates, recognizing the complexity of cumulative risk as it intersects with genetic factors.

Page 27: Exam Question

  • Prompt: Critically discuss how environmental factors during prenatal and postnatal periods may influence the risk of developing psychopathology.

Page 28: Core Reading

  • Essential and recommended readings covering various studies and findings related to environmental influences on psychopathology.

  • Notable citations include works by Roffman et al. (2021), Suleri et al. (2024), and others.

Page 29: Additional References

  • List of references augmenting core reading, including pivotal studies relating to perinatal mental health and environmental impacts on psychopathology.