Tricky Topics: Diathesis Stress

The video discusses the Diathesis-Stress Model of mental illness, which explores the interplay between genetic predispositions (nature) and environmental factors (nurture) in the development of psychological disorders, particularly Depression.

Key Scientific Concepts and Discoveries:

• Diathesis-Stress Model: This model suggests that both biological and environmental influences contribute to the occurrence of mental illness, emphasizing the interaction between genetic predispositions and life stressors.
• Genetic Factors: Certain genes, particularly those related to the serotonergic system, have been implicated in Depression. The Serotonin Transporter Gene exists in two forms (short and long), influencing how individuals respond to stress.
• Stressors and Depression: Life events that serve as stressors are associated with episodes of Depression. The model aims to explain why stressful experiences trigger Depression in some individuals but not in others.

Study Methodology:

• Longitudinal Study: A large-scale Longitudinal Study was conducted as part of the Dunedin Multidisciplinary Health and Development Study in New Zealand, following participants over decades.
• Sample: The study focused on 1,037 individuals from a 1972 birth cohort, with 847 followed up every two years during childhood and then again in young adulthood.
• DNA Sampling: At age 26, DNA samples were taken to identify the Serotonin Transporter Gene variants, and Depression symptoms were measured through clinical interviews.
• Life Events Assessment: Life events experienced between ages 21 to 26 were recorded using a life history calendar.

Findings:

• Individuals with low levels of life stress showed a low incidence of Depression, regardless of their genetic makeup.
• For those experiencing higher levels of stress, the type of serotonin transporter genes significantly influenced the likelihood of developing Depression:
  • Short/Short: Highest likelihood of Depression with four or more stressful life events.
  • Short/Long: Moderate likelihood.
  • Long/Long: Lowest likelihood.

Implications:

The Diathesis-Stress Model is gaining acceptance in explaining individual variability in mental illnesses beyond Depression, including disorders like Alzheimer's disease, schizophrenia, and ADHD.

Featured Researchers/Sources:

• Dunedin Multidisciplinary Health and Development Study (New Zealand)