3 ms·

Been a couple of years since I've closely tracked the literature on some of these questions. Regarding diagnosis and prevalence of ADHD in children and adults,

by jrapdx3 10y ago

Been a couple of years since I've closely tracked the literature on some of these questions. Regarding diagnosis and prevalence of ADHD in children and adults, the population rates are similar internationally (Germany, Brazil, US) provided that the same diagnostic criteria are used. The new standard criteria given in DSM5 and ICD10 may reduce regional differences in the the criteria that are applied. ADHD is one of the most studied conditions in terms of genetic predisposition. Across many studies the overall heritability is 0.75-0.80, denoting that 75% of the variability between affected and non-affected individuals is accounted for by genetic factors. IIRC the genetic risk of a child having ADHD if one parent has it is about 55-60%. The migration theories don't hold up well to closer scrutiny, for one thing only some ADHD sufferers are prototypical restless risk-takers. At least an equal proportion are quite risk-avoidant, and would be less inclined to pick up and move. Nonetheless ADHD may have evolutionary persistence because it confers reproductive advantage, though such advantages are hard to pin down. Perhaps energetic risky behavior is attractive or sexual impulsivity predisposes to having more children, but that's just speculation.

Amygaz 10y ago
You would think that any bold/risky phenotypes would balance itself out: - On one side, maybe ADHD-types reproduce more or are better disposed to make sure their offsprings get to a reproductive stage (e.g. wealthy, due to a bold move which payed out). - On the other side, their are also more likely to have taken a risky move, which end up costing them a lot, including their life, so no offspring or no additional support to support kin-selection.
- jrapdx3 10y ago
  It's true that ADHD adults have higher mortality from auto accidents, more health problems, higher divorce rates, greater unemployment, lower educational achievement than non-ADHD peers. Despite all their disadvantages, rate of ADHD occurrence in the population has been stable as far as can be determined. The inference is reproduction is not impeded, and may exceed the population mean in light of anticipated losses as you describe. I haven't specifically looked into this, not recently anyway, but data may well be out there. Anecdotally it's a common pattern to see ADHD adults having had numerous partnerships which are not sustained beyond a few years. Not surprisingly, an ADHD parent can wind up with children from these several partners as a result, leading to the hypothesis that instances of high birthrate offset the fraction of ADHD adults with low birthrate. Obviously, even a small positive offset in birthrate of all ADHD vs. controls would be sufficient to keep incidence of ADHD constant.

by jrapdx3 10y ago

Amygaz 10y ago

You would think that any bold/risky phenotypes would balance itself out: - On one side, maybe ADHD-types reproduce more or are better disposed to make sure their offsprings get to a reproductive stage (e.g. wealthy, due to a bold move which payed out). - On the other side, their are also more likely to have taken a risky move, which end up costing them a lot, including their life, so no offspring or no additional support to support kin-selection.

jrapdx3 10y ago
It's true that ADHD adults have higher mortality from auto accidents, more health problems, higher divorce rates, greater unemployment, lower educational achievement than non-ADHD peers. Despite all their disadvantages, rate of ADHD occurrence in the population has been stable as far as can be determined. The inference is reproduction is not impeded, and may exceed the population mean in light of anticipated losses as you describe. I haven't specifically looked into this, not recently anyway, but data may well be out there. Anecdotally it's a common pattern to see ADHD adults having had numerous partnerships which are not sustained beyond a few years. Not surprisingly, an ADHD parent can wind up with children from these several partners as a result, leading to the hypothesis that instances of high birthrate offset the fraction of ADHD adults with low birthrate. Obviously, even a small positive offset in birthrate of all ADHD vs. controls would be sufficient to keep incidence of ADHD constant.