https://joelniggphd.com/wp-content/uploads/2017/10/pexels-photo-235615-640x427.jpg 427 640 Joel Nigg https://joelniggphd.com/wp-content/uploads/2017/04/high-res-cover-1-1-200x300.jpg Joel Nigg2017-10-05 22:09:532017-10-05 22:09:53Genetics and Environment - Actionable ADHD Research
ADHD has important genetic influences, but increasing evidence suggests more environmental influences than previously believed. Yet the idea that ADHD could involve epigenetic effects, sometimes triggers surprising hostility. Sometimes, critics are unaware of the emerging field of behavioral epigenetics or of recent ADHD findings. Other times, they miss details or misunderstand the argument. Here’s a summary of the current state of the art on this topic:
First: epigenetic effects are ubiquitous, indeed, fundamental in human development. The idea that genes alone drive development was always simplistic and is now passe, at the level of biology.
Second: It is increasingly likely that many, perhaps all, complex diseases reflect the interplay of genetic liability and environmental amplification or buffering (even if a small number of cases involve a single major insult or single major mutation). The environmental effects, in turn, could operate via epigenetic effects–and probably do at least in part.
Third: Animal studies do show that experiences like stress, certain nutrition effects, pollutants, and exercise can have significant effects on developing brain and behavior, and at some of these effects include epigenetic changes.
Fourth: The ADHD literature has now shown intriguing, actionable findings for some of the safe experiential efforts like certain nutritional efforts. The developmental literature, meantime, is rife with data on effects of exercise and stress on learning, attention, and behavior, as well as on brain development; it is unlikely, therefore, that these are not somehow involved in ADHD. Indeed, preliminary ADHD studies seem consistent.
Finally, then, a very promising hypothesis is that ADHD involves some (still unknown) degree of epigenetic effects; if it does, this would account for a good deal of what is being observed and allow an exciting integration of genetic findings and developmental and environmental findings. Indeed, this seems like where the field of developmental psychopathology is heading. It is helpful that we recognize the possibility of epigenetic effects, because that makes sense of how the environmental findings in child development and in ADHD can complement the genetic findings. It also gives new hope for trying to combine environmental treatments. This is a helpful “framework” for thinking about how ADHD might work, how we should study it, and how we can help it. Meantime, regardless of how the biology finally is understood for ADHD, and recognizing there is a lot of individual variation in how this works, parents can still benefit now from the recent intervention findings to help their children–any many have. (If anyone would like citations for these points I’ll be happy to provide). In my book I outline all this in more detail for a non-expert audience and also point to some key scientific studies. Best wishes to all, JN