17.2.1 Genetic Vulnerability

• Addiction is a compulsive engagement with a substance or activity despite adverse consequences
• Physical dependence in addiction leads to tolerance and withdrawal symptoms
• Tolerance in addiction refers to needing more of a substance to achieve the same effect
• What does genetic vulnerability in addiction refer to?

  Increased susceptibility to addiction
• Specific genes can influence how the brain responds to substances, leading to a higher risk of compulsive use and dependence
• Twin studies in addiction compare identical and fraternal twins to estimate heritability
• What do family studies in addiction analyze?

  Family histories of addiction
• Steps in adoption studies to distinguish genetic vs. environmental factors

  1️⃣ Compare adopted individuals with biological parents

  2️⃣ Compare adopted individuals with adoptive parents
• Match the concept with its description:

  Heritability ↔️ Proportion of trait variation due to genetic factors

  Gene-environment interaction ↔️ Combined effect of genes and environment
• Specific genes, such as those regulating dopamine receptors, can influence the brain's response to substances
• Higher concordance rates in identical twins suggest genetic influence in addiction
• Match the study type with its benefit:

  Twin Studies ↔️ Estimate heritability; isolate genetic influence

  Family Studies ↔️ Identify inheritance patterns

  Adoption Studies ↔️ Differentiates genetic from environmental factors
• Dopamine genes regulate the production, transport, and reception of dopamine
• The DAT1 gene transports dopamine back into nerve cells
• What does lower density of DRD2 receptors affect in the brain?

  Dopamine sensitivity
• Serotonin genes are crucial for mood regulation and impulse control
• Short alleles of the SLC6A4 gene can increase vulnerability to addiction
• What is the function of the SLC6A4 (5-HTT) gene?

  Transports serotonin
• The biopsychosocial model of addiction highlights the role of genetics.
• Serotonin genes regulate the production, transport, and reception of serotonin
• Match the serotonin gene with its function:

  SLC6A4 (5-HTT) ↔️ Transports serotonin into neurons

  HTR2A ↔️ Codes for serotonin receptors
• Reduced serotonin uptake can lead to greater impulsivity and increased addiction risk
• What are the three key components of addiction?

  Physical dependence, tolerance, withdrawal
• Genetic vulnerability increases susceptibility to addiction based on genetic makeup.
• Variations in genes regulating dopamine receptors can make some individuals more likely to experience intense pleasure
• What do twin studies in addiction estimate?

  Heritability
• Adoption studies compare adopted individuals with their biological and adoptive parents.
• Match the genetic study type with its description:

  Twin Studies ↔️ Compare identical and fraternal twins

  Family Studies ↔️ Analyze family histories

  Adoption Studies ↔️ Compare adopted individuals
• Twin studies assume that identical and fraternal twins share equal environments
• Family studies can distinguish between genetic and environmental factors.

  False
• What is a limitation of adoption studies in addiction research?

  Small sample sizes
• Order the limitations of genetic studies in addiction research:

  1️⃣ Separating genetic from environmental influences

  2️⃣ Generalizing to all populations
• Dopamine genes influence the reward pathway
• What is the function of the DAT1 gene?

  Transports dopamine
• What role do serotonin genes play in addiction?

  Mood regulation and impulse control
• Variations in serotonin genes can significantly influence addiction risk.
• The SLC6A4 gene, also known as 5-HTT, transports serotonin back into neurons.
• Which gene is associated with reduced serotonin uptake and greater impulsivity in addiction?

  SLC6A4 (5-HTT)
• The reward deficiency syndrome in addiction is related to insufficient serotonin levels.
• Steps involved in the biopsychosocial model of addiction

  1️⃣ Biological factors (e.g., genes)

  2️⃣ Psychological factors (e.g., mood regulation)

  3️⃣ Social factors (e.g., environment)