Generally, pediatric mental health clinicians prefer to wait until the age of seven or so to diagnose ADHD, because so many of the symptoms (inattention, hyperactivity, impulsivity) of ADHD are typical of the behavior of yopung (particularly pre-school) children.
Having said this, it does happen that ADHD is diagnosed in pre-school children, and medication is sometimes prescribed in these circumstances. However, there is considerable debate about the appropriateness of such diagnoses, leading some to conclude that ADHD is over-diagnosed and medication over-prescribed in this young population.
A reasonable stance is that ADHD should be diagnosed, and medication prescribed, only in the most serious (even severe) situations in children as young as your son.
Can you please tell me if any, are there any other symptoms
of ADHD and what they are?