La Coop P.A.- General and Forensic Psychiatry - Boutique-Private Psychiatric and Forensic Practice in Tampa-Clearwater-Florida


March, 2013- FOCUS ON SUBSTANCE ABUSE: Nature versus Nurture??


So, many of you know that I deal with substance abuse problems regularly in my treatment of patients. Whether it's themselves or a sibling or spouse - substance abuse causes serious hurt (medically, financially, legally, socially, psychologically, etc.).

A lot of patients ask me where this comes from? Many patients tell me that there is no family history of substance abuse and they don't know where it comes from, and on the other hand - there are patients that come from a long line of substance abusers, but they themselves do not abuse.

This article in the February 2013 issue of the Journal of the American Medical Association - Psychiatry is entitled, Within-Family Environmental Transmission of Drug Abuse and it discusses a study done in Sweden. It's a fantastic article that may help you to understand the factors involved in substance abuse and it's transmission to others.

If you have any ideas for the newsletter, please email me!

Dr. L

Within-Family Environmental Transmission of Drug Abuse Kendler KS, Ohlsson H, Sundquist K and J

This research study wanted to figure out how much of substance abuse is due to genetic factors or environmental factors. We all know that each of these factors has an impact on a persons proclivity to use substances. They just wanted to determine which ones and how much.

Essentially they researched relationships in drug abusers lives and found the following:

  • Drug abuse is more common in same sex pairs of siblings.
    So, brothers are more likely than sisters to have drug abuse problems, but also when there are 2 brothers in a family and one has a drug abuse problem (likely the older sibling, see below) - it is more likely for the other brother to also have a drug abuse problem. However, the researchers couldn't tell whether that was purely genetic or environmental.
  • Drug abuse transmits more in siblings that are closer in age.
    In their research, the authors determined that the risk for drug abuse was nearly twice as great for a sibling born in the same year as a drug abusing sibling as it was for a sibling born 10 years apart. This indicates more of an environmental factor as all siblings are genetically similar.
  • Drug abuse seems to go from oldest sibling to younger, not the other way around.
    Having an older sibling with drug abuse conveys a 42% greater risk for drug abuse than having a younger drug abusing sibling. Again, the risk is greater in 2 brothers than 2 sisters. An abusing older brother carried much more risk for his younger brother than vice versa.
  • Adults with drug abuse commonly get together with other drug abusing people romantically and have a tendency to get married to a drug abusing partner.
    Husbands with drug abusing wives and wives with drug abusing husbands had equally elevated risks.

So, this article was interesting because it shows that not only is there a purely genetic component to substance abuse, but there is a significant environmental factor as well.

So, it is who you allow your kids to hang out with - not only the genetics. But, it is important to note that genetics plays a large role as well, in terms of the genetic and environmental factors playing equal roles. The siblings that your child hangs out with is also very important. Who they relate to, and who they look up to.

I hope this helped some of you put your minds around the nature versus nurture component of substance abuse.

Until next month!

Dr. L

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