*Genetic Contributions to Psychological Disorders

Overview of Genetic Contributions to Depression

  • Depression and Genetic Contributions Interaction

    • Genetics plays a role in the development and interaction of depression with various factors.

Chromosomes and Karyotypes

  • Karyotype:

    • An organized picture of all chromosomes in a cell, arranged by size, shape, and number.

    • Humans have a total of 46 chromosomes arranged in 23 pairs.

    • 22 pairs are autosomes (non-sex chromosomes).

    • 1 pair of sex chromosomes:

      • XX = Female

      • XY = Male

Structure of DNA

  • Deoxyribonucleic Acid (DNA):

    • Chromosomes are made up of DNA, which is an essential molecule for genetic information.

    • DNA consists of four organic compounds:

    • Adenine (A)

    • Thymine (T)

    • Cytosine (C)

    • Guanine (G)

    • These compounds are organized into base pairs that form the characteristic double helix structure of DNA.

Genetic Disorders and Their Inheritance

  • Inherited conditions can be categorized as:

    • Single gene disorders

    • Polygenic disorders:

    • Examples of polygenic disorders include:

      • Diabetes

      • Schizophrenia

      • Autism

  • Chromosomal Disorders:

    • Abnormalities in the number or structure of chromosomes during reproduction can lead to several disorders such as:

    • Down Syndrome (Trisomy 21)

    • Turner Syndrome

    • Klinefelter Syndrome

Environmental Interactions

  • Environment Matters:

    • Environmental factors have a significant impact on health and genetic expression.

    • Actions in the environment can affect the Epigenome:

    • This relates to external modifications to DNA that turn genes on or off without changing the sequence.

Models of Interaction

  • Diathesis-Stress Model:

    • This model posits that people have varying levels of vulnerability (diathesis) to stress, affecting their likelihood of developing psychological disorders.

  • Gene-Environment Correlation Model:

    • This model emphasizes how genetic predispositions can influence the types of environments individuals choose or are exposed to, thus impacting psychological health.

  • Overall, the equation can be summarize:

    • GENES + ENVIRONMENT = PSYCHOLOGICAL DISORDER (A)

    • Where genetic susceptibility is described as diathesis, which refers to a predisposition to develop certain disorders, influenced by environmental factors such as stress.