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.