1. From Genes to Behavior: What does being “genetically at risk” for addiction really mean?
Keith Chen
Danielle M. Dick, Ph.D.
Virginia Commonwealth University
Departments of Psychology
and Human & Molecular Genetics

2. Things we know about substance use problems
We’re not all equally at risk
Genetic influences are important

3. How do we know something is genetically influenced?
MZ Twins
DZ Twins
100% shared genetic variation
100% shared home environment
50% shared genetic variation
100% shared home environment
If MZs > DZs → Genetic Influence
If DZs = MZs → Shared Environmental Influence
If MZs < → Unique Environmental Influence

4. Psychiatric Disorders Other Important Familial Traits ~zero
Heritability
Psychiatric Disorders
Other Important Familial Traits
~zero
Language Religious Affiliation
20-40%
Anxiety disorders
Depression
Bulimia
Myocardial Infarction
Personality, Breast Cancer,
Hip Fracture
40-70%
Alcohol and drug dependence,
Antisocial Behavior
Blood Pressure, Asthma
Plasma cholesterol, Prostate Cancer, Adult-onset diabetes
70-80%
Schizophrenia
Bipolar Illness
Weight,
Bone Mineral Density
80-100%
Autism
Height, Brain Volume
This is how the heritability of alcohol and drug dependence compares to other biomedical traits and disorders. But knowing that a disorder is under genetic influence is really only the first step in understanding genetic influences on addiction. There are a variety of more complex questions we can address about how genetic influences act…
Slide courtesy of Ken Kendler, M.D.

5. Psychiatric Disorders Other Important Familial Traits ~zero
Heritability
Psychiatric Disorders
Other Important Familial Traits
~zero
Language Religious Affiliation
20-40%
Anxiety disorders
Depression
Bulimia
Myocardial Infarction
Personality, Breast Cancer,
Hip Fracture
40-70%
Alcohol and drug dependence,
Antisocial Behavior
Blood Pressure, Asthma
Plasma cholesterol, Prostate Cancer, Adult-onset diabetes
70-80%
Schizophrenia
Bipolar Illness
Weight,
Bone Mineral Density
80-100%
Autism
Height, Brain Volume
This is how the heritability of alcohol and drug dependence compares to other biomedical traits and disorders. But knowing that a disorder is under genetic influence is really only the first step in understanding genetic influences on addiction. There are a variety of more complex questions we can address about how genetic influences act…

6. Psychiatric Disorders Other Important Familial Traits ~zero
Heritability
Psychiatric Disorders
Other Important Familial Traits
~zero
Language Religious Affiliation
20-40%
Anxiety disorders
Depression
Bulimia
Myocardial Infarction
Personality, Breast Cancer,
Hip Fracture
40-70%
Alcohol and drug dependence,
Antisocial Behavior
Blood Pressure, Asthma
Plasma cholesterol, Prostate Cancer, Adult-onset diabetes
70-80%
Schizophrenia
Bipolar Illness
Weight,
Bone Mineral Density
80-100%
Autism
Height, Brain Volume
This is how the heritability of alcohol and drug dependence compares to other biomedical traits and disorders. But knowing that a disorder is under genetic influence is really only the first step in understanding genetic influences on addiction. There are a variety of more complex questions we can address about how genetic influences act…

7. Psychiatric Disorders Other Important Familial Traits ~zero
Heritability
Psychiatric Disorders
Other Important Familial Traits
~zero
Language Religious Affiliation
20-40%
Anxiety disorders
Depression
Bulimia
Myocardial Infarction
Personality, Breast Cancer,
Hip Fracture
40-70%
Alcohol and drug dependence,
Antisocial Behavior
Blood Pressure, Asthma
Plasma cholesterol, Prostate Cancer, Adult-onset diabetes
70-80%
Schizophrenia
Bipolar Illness
Weight,
Bone Mineral Density
80-100%
Autism
Height, Brain Volume
This is how the heritability of alcohol and drug dependence compares to other biomedical traits and disorders. But knowing that a disorder is under genetic influence is really only the first step in understanding genetic influences on addiction. There are a variety of more complex questions we can address about how genetic influences act…

8. Psychiatric Disorders Other Important Familial Traits ~zero
Heritability
Psychiatric Disorders
Other Important Familial Traits
~zero
Language Religious Affiliation
20-40%
Anxiety disorders
Depression
Bulimia
Myocardial Infarction
Personality, Breast Cancer,
Hip Fracture
40-70%
Alcohol and drug dependence,
Antisocial Behavior
Blood Pressure, Asthma
Plasma cholesterol, Prostate Cancer, Adult-onset diabetes
70-80%
Schizophrenia
Bipolar Illness
Weight,
Bone Mineral Density
80-100%
Autism
Height, Brain Volume
This is how the heritability of alcohol and drug dependence compares to other biomedical traits and disorders. But knowing that a disorder is under genetic influence is really only the first step in understanding genetic influences on addiction. There are a variety of more complex questions we can address about how genetic influences act…

9. GENE
for…

10. Bodies and Brains
Substance
Use
Problems
Genes

11. Things we know about substance use problems
We’re not all equally at risk
Genetic influences are important
There is no one predisposition or genetic pathway to substance use problems
Shows up in different ways across development

12. Just an example from another project showing different pathways of risk

13. Pathways of Genetically Influenced Risk for Substance Use Outcomes
Physiological: the way our bodies respond to a drug
Externalizing: impulsivity, sensation-seeking
Internalizing: anxious, depressed, drinking to cope
So what we know from our research is that there are different pathways by which individuals engage in risky drinking. One factor is physiological response…Other people are more high sensation-seeking, others drink to cope. So there are very different reasons why people drink, but alcohol programming is all one size fits all. Imagine if when you went in to your primary care physician for a wellness check, instead of asking you about you’re your behavior and talking to you about your risks, they rattled off all the health risks for someone of your age. Probably not the most effective way to go. We can do better.
(We all have our own unique combination)

14. Physiological Response
Alcohol dehydrogenase genes – involved in the breakdown of ethanol
Unpleasant response – less likely to develop problems!
Low level of response to alcohol
more drinks to experience intoxicating effects
have to drink more than average to experience effects
heavier drinking can lead to more problems

15. Pathways of Risk for Substance Use Outcomes
Physiological: the way our bodies respond to a drug
Externalizing: impulsivity, sensation-seeking
Internalizing: anxious, depressed, drinking to cope
So what we know from our research is that there are different pathways by which individuals engage in risky drinking. One factor is physiological response…Other people are more high sensation-seeking, others drink to cope. So there are very different reasons why people drink, but alcohol programming is all one size fits all. Imagine if when you went in to your primary care physician for a wellness check, instead of asking you about you’re your behavior and talking to you about your risks, they rattled off all the health risks for someone of your age. Probably not the most effective way to go. We can do better.

17. So what do we know about how genes influence addiction?
There are no genes “for” substance problems
Genes influence the way our bodies respond to drugs, as well as our personalities and temperaments, which can put us more or less at risk for developing problems
Dispositions are not destiny

18. COLLEGE BEHAVIORAL AND EMOTIONAL
HEALTH INSTITUTE
cobe.vcu.edu