evidence: Few psychiatric disorders have stirred up as much controversy and as many strong opinions as attention-deficit/hyperactivity disorder (ADHD), with claims that it is overdiagnosed or does not exist at all, and that children are being drugged with potentially dangerous medications for normal naughtiness or fidgetiness so as not to inconvenience teachers and parents. Factors that would seem to lend credence to the claim that ADHD is not a real disorder are the fact that (like almost all psychiatric disorders) the diagnosis is made purely by clinical impression, as there is no definitive biological test—or even a definitive cognitive test—for its diagnosis, and the symptom criteria can be interpreted quite broadly to apply to a large proportion of people. [...] As ADHD diagnoses and stimulant prescriptions increased, public doubt increased regarding the validity of the diagnosis and the justifications for treatment. Critics argued that ADHD is an unnecessary medicalization of children who are not ill but who simply display challenging behavior.19 Some argued that the diagnosis was invented or greatly expanded purely to serve the financial interests of drug companies.20 [...] 19. Alternatively, it has been argued that ADHD is not a disease as such but rather a cluster of non-specific symptoms that are a final common behavioral pathway for a range of emotional, psychological, and/or learning problems.