5 thoughts on “The Who, What, Where, Why and Huh? of ADHD, Part III: Where Does ADHD Come From?

  • March 22, 2010 at 7:10 am

    Actually, when I read on I think it was Barkley’s website that ADHD was estimated at 80% heritability, based on things like twin studies and adoption studies, Barkley pointed out that that 80% figure was the same as the degree of heritability for height. (Actually, I’m not sure if it was Barkley – it might have been Brown.) Yes, your height can be influenced by malnutrition, failure to thrive, environmental stressors, etc, but there is a big genetic component. And it’s the same with ADHD.

    As for adoption studies, not all adoption studies were done with twins. What adoption studies not done with twins show is that the adopted child is much more likely to have ADHD if the birth parent had it, even when that child had minimal to no contact with the birth parent. Since the birth parent had ADHD, that fails to support the conclusion that the child’s ADHD is simply the result of the fact that they were adopted, instead supporting the genetic theory.

    I might add that the well known tendency for ADHD to run in families supports the genetic theory not only by the fact that it does run in families, but also by the fact that while some relatives of an ADHD person typically have ADHD, usually not all relatives have this disorder. I say this supports the genetic case because it demonstrates a familial tendency but the fact that it is not universal among children raised in the same family environment lessens the chances somewhat of it being solely a product of that environment. Take my family, for example. I, the oldest, and my brother, the youngest, both have ADD. My sister, who is in the middle, does not.
    Being the middle child, she was the person who experienced the most overlap between both her and my childhoods and her and my brother’s childhoods. (As I was 5 1/2 years older than he was, I was not so close to him as far as being in the same stage of childhood at the same time.) So basically, she experienced nearly the same home environment in her childhood as I did and as her ADD brother did, yet she did not develop ADD.

    I’m writing this at 3 am, so my apologies if I’m rambling – I hope it makes sense.

  • March 22, 2010 at 7:24 am

    The 100% shared genes of twins without a 100% concordance rate suggests to me that the tendency to develop ADHD is genetically inherited; however, we are still influenced by factors in our early child development, etc., that can influence the way our neuronal connections develop in the long run. Sounds very similar in this way to schizophrenia, which has an inherited high likelihood of development, but not certain – the rest seems to depend on the presence or absence of factors like environmental stressors. Perhaps for ADHD, these environmental factors might be things like whether the child was raised in a structured, calm, environment and encouraged to do things that helped develop his/her attention span. (That’s just speculation, but I’m guessing that if I had time to look up research, it might support that theory!) Also, I think I read that authoritarian parenting practices can have an impact on hyperactive and defiant behavior – I don’t think those have an impact on inattention, though.

    Regardless, ADD seems to be a largely inherited predisposition which in some cases is overcome or exacerbated by environmental factors. (This is talking about the 80% of cases that are hereditary, of course.)

  • March 22, 2010 at 9:21 pm

    For me I have come to believe that it has to do with epilepsy which later developed into full blown Gran Mal seizures. I think that ADHD is merely a grouping of symptoms but not the disease itself and in fact these symptoms could come from a variety of sources including genetic and environmental.

  • March 24, 2010 at 3:24 pm

    Hi, I am the oldest of 4 children. I’m 37 and I wasn’t diagnosed until 6 years ago. My father had ADHD and also my two younger brothers. I have 3 children and my middle child has ADHD and my oldest possibe ODD. My sister does not have ADHD but it may be possible, although undiagnosed, her oldest daugter and youngest son may have it. After I had my 11 year old son I had a grand mal seizure in the hospital. They have continued until the present. Especially around my period. This also runs in my cousins family. I did have a SPECT scan which showed the “ring of fire” ADHD. The symptoms psychologically are very similar. I did have symptoms as a child but worked it out and worked very hard for some A’s but mostly C’s. Oh, through EEG’s they found it was in my left temporal lobe. Hormonal changes play a very large role in my symptoms. I read about IDD. Interectal Dysphoric Disorder. It is not proven yet. But, in between seizures mood changes and ADHD symptoms change. It was a very interesting article. If anyone has more info I would greatly appreciate it. It seems as though there are so many factors and so many overlapping symptoms in general in psychology. Psychiatrists can’t properly diagnose in 10 minutes. I finally foun someone to spend an hour and a half to figure it out. He saved my life. Also, Neuropsychiatrists are rare and hard to find. Why should they even be separate in the first place? Thanks, Nikki

    • March 24, 2010 at 7:21 pm

      Nikki, wow, so much information! Thank you for sharing with us. I agree it’s a complicated path we walk. The one thing I know for sure, is how much better I feel, personally, that I’m not alone. Lately, for me, the most positive stance I can take is to focus on how to make my life better; how to be kinder to myself and others; and that research continues to point to the malleability of the human brain, and maybe, just maybe, I can build some more functional pathways even at this late stage of the game! All the best to you, and thanks for reading and sharing.


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