Psychiatry & Psychotherapy Podcast Genetic and Environmental Influences of Schizophrenia
Nov 7, 2025
Dr. Liam Browning, a psychiatrist specializing in psychiatric genetics, teams up with Dr. Nicholas Fabiano, an expert in psychiatric epidemiology, to delve into the intriguing interplay of genetics and environment in schizophrenia. They explore the significance of heritability, the implications of childhood trauma, and the cannabis-hallucinogen connection to psychosis risk. Also discussed are prenatal factors, genetic findings from studies, and the ethical dimensions of genetic testing. The conversation highlights the need for person-centered care and preventive strategies in mental health.
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What '80% Heritable' Really Means
- Heritability estimates (like “80% heritable”) describe population variance, not individual risk.
- Heritability rises when environments are uniform and falls when environments vary across a population.
Twin Concordance Is Lower Than You Think
- Monozygotic twin concordance for schizophrenia is far lower than often assumed (roughly 15–35% in modern estimates).
- Identical genes do not guarantee identical outcomes because nonshared factors and prenatal influences matter.
Candidate-Gene Era Produced False Positives
- Candidate-gene studies produced many false positives due to multiple-comparison issues and publication bias.
- Early hopes for single-gene causes (like dopamine genes) largely failed to replicate.