Alcoholism: Genetic Variance and Different Treatment Outcomes

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Alcoholism: Genetic Variance and Different Treatment Outcomes




Guest:  Dr. Ray Anton - Psychiatry & Behavioral Sciences

Host:  Dr. Linda Austin – Psychiatry


Dr. Linda Austin:  I’m Dr. Linda Austin.  I’m interviewing Dr. Ray Anton, Professor of Psychiatry in Behavioral Sciences here at the Medical University of South Carolina.  Let’s talk about this very interesting question that you have researched, the question of why it is that some people seem to respond to naltrexone and others do not.


Dr. Ray Anton:  Right.  That’s a very important question because, as we talked about previously, not everybody does respond to naltrexone.  Underlying this difference in response is probably their unique biology.  Everybody is an individual, and it all goes down to their genetic level, what they were born with.  Nationally, science, right now, is trying to understand why people respond to medication and why some do not.  Much of the focus has been on genetic differences and genetic diversity.


So we use that approach to try to understand why some people respond to naltrexone for treatment of alcohol dependence and why others do not.  There are small bits of DNA and it may be only a few percent of the total amount of DNA.  So there’s quite a bit of diversity in how people might respond to medication based on their genetic structure, the small differences in the DNA that occur in their genes.


Dr. Linda Austin:  Essentially, in your research, then, you ask the question, could there be differences in genes that then lead to different proteins on the cell in a part of the brain where opiates bind that is also where the effects of alcohol are seen, could there be differences, one person to another, and could that translate into whether that person responds to naltrexone or not?  Is that right?


Dr. Ray Anton:  That’s basically it.


Dr. Linda Austin:  So, Dr. Anton, earlier you said that people who are likely to get euphoric when they drink alcohol are those who have reactions involving endorphins binding to proteins.  They release endorphins that bind to the proteins and they get a high, as opposed to other people who are more likely just to get sleepy.  Now, how, then, does naltrexone play into that, and how does this gene play into that?


Dr. Ray Anton:  Endorphins that are released by alcohol bind to this specific receptor in the brain, one of the opiate receptors in the brain.  Some people that become alcohol dependent because of their gene structure may be more sensitive to this endorphin release and binding.  Not all alcoholics may be in that category.  This is only one mechanism of maybe a number that causes people to drink.  People with this genetic difference, or genetic variant, that has been discovered seem to have more of a bang from the alcohol, so to speak; it’s more of a wow factor.  And we might consider them to be, you know, endorphin alcoholics, for lack of a better word. 


Those people, hypothetically, should respond more to blocking the actions of the endorphin.  And that’s what naltrexone does.  It blocks the action of the endorphin.  So if they do drink, or if they’re in the situation where drinking normally occurs, and they’re naturally releasing these endorphins, naltrexone blocks them from working so they don’t get stimulated.  They don’t have craving.  They don’t have the urge to drink or to drink more in those situations.  So, it allows them to keep control, to use natural resistance mechanisms to not drink or to talk about their drinking and get support from significant others, from AA members, their family, or their physicians or counselors.  So, it acts as a way of sort of slowing down, perhaps, the natural buzz process that people would get from alcohol and gives them a fighting chance to assist themselves in their own recovery.


Dr. Linda Austin:  And I think it’s important, also, to underline, as many scientists have, that a gene doesn’t cause behavior; the gene doesn’t cause alcoholism.  But the gene can affect the way a person responds to alcohol.


Dr. Ray Anton:  That’s correct.  Think of it more as a risk factor.  Like, obesity doesn’t cause diabetes, but obese people are more at risk for developing diabetes.  So, there’s an interaction between behavior and genetics.  So, one cannot become an alcoholic unless they drink alcohol.  So, there’s an interaction between genes and how you respond to alcohol.  And now we know that there’s an interaction between genes and medication, of how people may respond to the treatment for alcohol as well.


Dr. Linda Austin:  In your study, you also looked at cognitive behavioral therapy.  What were your findings there?


Dr. Ray Anton:  Cognitive behavioral therapy is a specialized therapy which is used in many psychiatric conditions such as depression and anxiety.  It’s a special type that’s been designed to help people with alcohol dependence in particular.  Some people call it relapse prevention therapy or coping skills development.  But, basically, it’s a unique therapy that is delivered by a trained professional.  An addiction professional is either a psychologist or a social worker, and MDs as well, who are doing that kind of work.


In the past, a number of studies have shown it to be pretty effective in its own right, compared to doing nothing or just doing supportive counseling, which does not allow people to understand the roots of their craving and how to manage drink refusal skills, how to manage anger and frustration, the types of things that may drive people to drink.  In a current study, what we found was that naltrexone and cognitive behavioral therapy were about equal, but they didn’t add anything to each other, which was different than what we had thought previously.


Dr. Linda Austin:  So a patient could choose one or the other, but wouldn’t necessarily have to have both at the same time?


Dr. Ray Anton:  That’s what the combined study would suggest.  On the other hand, I think if one wanted to be doubly sure, clinically, one could still, perhaps, make the case of using both together, particularly if you can’t predict who is going to respond to naltrexone, which is the interesting thing.  Because, if you do the genetic test and it looks like you have the type of genetic structure that says you’re not going to respond to naltrexone, in that case, you know, maybe you want to do cognitive behavioral therapy.  If the genetic test isn’t available, maybe doing both makes the most sense because one of them is likely to work.


Dr. Linda Austin:  How widely available is the genetic test at this time?


Dr. Ray Anton:  Well, it’s still pretty much in its infancy.  It’s something that wasn’t discovered too long ago.  Our lab here, at the Institute of Psychiatry, at MUSC, is in the process of setting up the test to do clinically.  And people entering our studies here often get that test as part of the research.  But hopefully within a few months, maybe by the summer of 2008, we can offer the test clinically here, at MUSC.


Dr. Linda Austin:  Dr. Anton, thank you very much.


Dr. Ray Anton:  Thank you.


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