That is a myth, the effects are the same regardless of whether or not you have ADHD otherwise we'd be able to test for ADHD by simply giving someone amphetamines and seeing how they respond. Almost anyone who takes low-dose amphetamines will experience enhanced cognition. It just happens that this enhancement also alleviates symptoms of ADHD.
As you pointed out the problem with the article is that it makes no distinction between therapeutic low-dose usage and abuse level usage.
As you pointed out the problem with the article is that it makes no distinction between therapeutic low-dose usage and abuse level usage.