addiction genes

Question 1

how are addiction genes identified

Answer 1

genome-wide methods and candidate gene studies. family based samples to test for consistent genes (National institute of health)

Question 2

Virginia twin study

Answer 2

show that initiation and use of nicotine, alcohol and cannabis more determined by familial/social factors. gradually decline in importance. middle age genetic factors become maximal

Question 3

Goldman

Answer 3

heritability ranges from +.39 for hallucinogens to +.72 for cocaine

Question 4

Role of DRD2 gene

Answer 4

dopamine receptor gene. A1 variant causes fewer dopamine receptor in pleasure centre. takes more to make them happy so they overstimulate through indulging in addictive behaviour.

Question 5

Comings et al

Answer 5

25.9% of general population have A1 variant of DRD2
48.7% of smokers and ex-smokers
50.9% of gamblers

Question 6

what are ADH and ALDH genes for

Answer 6

metabolising alcohol. alcohol dehydrogenase breaks alcohol down into acetaldehyde. acetaldehyde dehydrogenase breaks it down to acetic acid and water

Question 7

high activity enzymes

Answer 7

some gene variants result in high activity enzymes. the increase in acetaldehyde levels increase negative symptoms of drinking (face flushing, nausea). makes drinking less pleasant so alcoholism less likely.
variant most common in east Asia where there is less alcoholsim

Question 8

low activity enzymes

Answer 8

alcohol broken down slowly so onset of negative symptoms delayed and they can drink more. may be more vulnerable to alcoholism.

Question 9

Higuchi

Answer 9

lower activity variants of ADH genes jave increased rate of alcoholism in oriental populations

Question 10

CHRNA5

Answer 10

CHRNA5 codes for proteins that help sense nicotine.
people with two copies of a certain form of CHRNA5 2x likely to become nicotine dependent compared to two copies of different allele.

Question 11

mice research

Answer 11

mice that make more protein from Mpdz gene experience less severe withdrawal symptoms from alcohol and sedative-hypnotic drugs

Question 12

genes and treatment

Answer 12

understanding how genes cause bio differences helps develop treatments. drugs that modify activity of proteins made by genes. gene therapy

Question 13

diathesis stress model

Answer 13

addiction develops when genetic predisposition interacts with environmental stressor

Question 14

pharmogenetics

Answer 14

different patients benefit more from different medications. Anton- those with specific gene mutation more likely to abstain from alcohol on naltrexone. genetic tests could be used to find best medication. cost effective in the long run

Question 15

disease model

Answer 15

suggests addiction is a biological disease. could lead to dependency on others/medication and a lack of accountability. or low self esteem leading to more use of addiction. but reduces patient blame

Question 16

deterministic

Answer 16

suggests specific genes cause addiction, help with early detection and early intervention to prevent. aware they are more at risk. reduces patient blame. but lack of accountability.

Question 17

social and cultural factors

Answer 17

Kendler - studies female Swedish twins born 1910-58. higher heritability of tobacco use in later years of study. changing attitudes, more acceptable for women to smoke.

Question 18

Ojelade et al and continuation of research

Answer 18

found that faulty Rsu1 gene in fruit flies lowered sensitivity to alcohol. further research could reveal other genes impacting peoples vulnerability to addiction.
but means there is no one gene. also diff genes interact differently with different substances