He is right in the sense that adhd could be a cluster of symptoms, originating for a multitude of background causes.
Perhaps the the author of the article has got the interpretation slightly wrong. See, the first hand medicine that is usually prescribed for both children and adults is Not amphetamines. Ritalin and Concerta etc are not amphetamines.
Dextroamphetamine can be prescribed if methylphenidat/Ritalin does not have a therapeutic effect.
And remember. .. so many people get an incredible life changing help from these meds. No matter what this writer and doctor claims.