It's very real.

It's highly studied and *mostly* psychologically and physiologically understood, insofar that the main (theorized) issue - dopamine dysregulation in the brain that causes disorders of executive functions - is effectively treated with CBT, lifestyle changes, and stimulants (among other medications that target dopaminergic system or otherwise).

In those without ADHD, the same treatments are not helpful, i.e. their brain has plenty of dopamine, so something else is wrong. That's a gross oversimplification, but even the mere fact of having a diagnosis will help you and those close to you understand why your brain works the way it works, and begin your path in developing strategies to work around those "executive dysfunctions." It'll also give you the ability to work with your psychiatrist to try different medicines/dosages/therapies/lifestyle changes that will most certainly help.

The idea of it not being real comes from this idea that certain parents seek the diagnosis to "fix" or have a reason for their (mental) hyperactivity (bad grades, getting in trouble, etc). These are also parents who provide far too little stimulation, attention, exercise, and enrichment to their children. Some have turned it into a conspiracy or a societal flaw because the main treatment is stimulants. The irony is that because ADHD is genetic, there's a great likelihood that the parent themselves has undiagnosed ADHD and a result of their disorder was providing too little enrichment for their child, which (caveat: nature vs. nurture is up for debate) probably had a negative effect on the resident ADHD traits, exposing and possibly worsening them to the point of it being a problem. ADHD was not a diagnosed condition in the boomer/genX generation because, well, doctors sucked. Kid not paying attention? Yell at them. Kid having bad grades? Take away their fun. Kid getting into trouble? Spank them.

Yes, that stimulant is amphetamines. And one can abuse it, get high on it, and succumb to addiction. But the dosages in ADHD treatment are extremely low - just enough that there is a perceptible change in executive function that significantly diminish those hyperactive traits of the ADHD brain. To a person with ADHD, it's like putting glasses on for the first time. The brain does build up a tolerance, so if it's not properly administered under the care of a psychiatrist, it can become ineffective or the user can self-medicate beyond safe levels. That's why ADHD treatment must be a life-long, holistic approach where medicine plays an important role as much as diet, exercise, moderation, therapy, etc. But that's not to say it's a debilitating illness; ADHD people are extraordinary creative minds, are often incredible crisis, high-pressure environment workers (paramedics, dispatchers, ER surgeons, mission control operators lol), and are really really good at deeply focusing their passion on one thing in an almost superhuman way (lawyers, gamers (speed runners holy shit), writers, artists etc)

Now, that more people are getting ADHD diagnoses (and capitol punishment is abolished lol), it's normalized to the point where taking ADHD medications is almost no different than using glasses to correct blurry vision - as it should be. Documentaries on the subject are still overwhelmingly negative brainwashing attempts by crazy people (big pharma drugging our kids with adderall bad), and it's still got a long way to go (even the name Attention Deficit Hyperactivity Disorder sucks, while the term Neurodiversity is making strides as a general replacement for labels of common mental disorders)...but think about how far we've come.

Note: I'm making some unscientific, unfounded claims here backed up only by way too much hyperfocused reading on the topic. I'm currently seeking an ADHD diagnosis myself, because so many of my traits (and my parents) are explained by it (that I always thought were just normal struggles), and some prescribed stimulant medication for weight loss (appetite suppression) unlocked a side of me I never thought probable.