Does high IQ give cause to doubt an ADHD diagnosis? My friend was diagnosed with ADHD as a kid, but her parents disagreed with such a diagnosis on the grounds that she had a high IQ which was discovered when her psychologists and psychiatrists were investigating what mental illnesses she may have had.

Edit: There was medicine prescribed, but she and her mother can't remember the name of her prescribed medicine.

I thought back to that when reading this:


  Myth #10: Kids with ADHD won't amount to anything.
  
  Many famous artists, scientists, and politicians had ADHD as children.
  Here's a list of some well-known celebrities with ADHD:


It seems to me based on that and the things I've heard that people think ADHD in children causes poor academic performance, but the myth is that such poor academic performance is suggesting that said children "won't amount to anything".

So, people don't think that children with ADHD can be geniuses?

Expansion: Is it, however, also a misconception (whether as prevalent as a myth or not) that people who are thought to have mental illnesses instead are geniuses or something like that?

By genius I mean someone with a high IQ.
Sounds to me like someone is making a logical fallacy here, though the origin of this fallacy isn't clear to me.

We cannot go from 'poor academic performance', to 'not amounting to anything', to 'having a low IQ'. These are not relationships of cause and effect.

The motivation to do something ('amount to something', if you will) is driven primarily by the reward-center. The neurotransmitter 'dopamine' is considered to be a large player in this game. Dopamine tends to project to the areas associated with reward (and these areas are clustered into the abstraction known as the pleasure center). Incidentally, ADHD has shown to be a dysfunction of executive reasoning as a result of low dopamine levels.

IQ is not determined by executive functioning. IQ is almost independent of executive functioning. If they were interchangeable, then Albert Einstein would have a very low IQ compared to, say, Donald Trump. I say that it is 'almost' independent because it is not clear that there is no relationship between the two at all. Studies have shown that ADHD sufferers show an average increase of 4.5 IQ points after long-term use of dopamine-reuptake inhibitors. [1]

You might also be interested in this page to answer the second part(?) of your question. It is well-written and extremely insightful.



Sources:

[1] Millichap JG (2010). "Chapter 3: Medications for ADHD". In Millichap JG. Attention Deficit Hyperactivity Disorder Handbook: A Physician's Guide to ADHD (2nd ed.). New York: Springer. pp. 121–123.