Since lazulisong is taking on the issues regarding why it's so important to know something about ADHD if you're planning to write a character who has it, I get to focus on what that actually means.
Now, my experience is going to be different from other people's experiences of ADHD - I'll explain more about that in a moment - but, happily for relevance to Teen Wolf fandom, at least, Stiles appears to manifest it more-or-less exactly like I do, so I feel like I have a pretty good sense of what's going on with his.
So, let's start with the condition itself, in the helpful format of a Q&A.
What is ADHD?
ADHD stands for Attention Deficit/Hyperactivity Disorder. You may also hear people talk about ADD, which simply stands for Attention Deficit Disorder, but that's sort of a sign that they might not really know what they're talking about, because ADD is an out-of-date term, really. ADD is kind of a subset of ADHD; it's generally used for people who don't strongly manifest hyperactivity or impulsivity. It's still the same disorder, because it has the same physical cause.
Wait, what? Isn't ADHD a behavioural problem?
The short answer is: "No."
The slightly longer answer is: "No, and bite me."
The longer, and more helpful, answer, is quite a bit longer. However, ADHD is in fact a medical condition with physical causes, and is not caused by bad parenting or too much sugar or anything like that. (Although those things can cause misdiagnosis by lazy or incompetent medical personnel.)
Okay, so what does cause it?
I'm going to go with the massively simplified version of the neuroscience behind it, because brains are weird and unsimplified discussion of them gets very complicated indeed.
Brains are made up of neurons. Neurons connect with each other to transmit electrical impulses, and these convey all the vast, vast quantities of data your brain is processing at any one instant.
The outside of a neuron is a protein sheath (like a protective coating) which limits the electrical impulses so that the transmissions are controlled.
If the sheath isn't thick enough, it's like the neurons short-circuit. The electrical impulses hit too many neurons, aren't very controlled, and your brain becomes a sparking, chaotic mess.
The term for this is ADHD.
The reason why ADHD is mostly associated with children is that something like 70% of children grow out of it in their teens, and many more find the symptoms reduce. According to my psychiatrist, the reasons for this aren't completely known, but the popular theory is that the hormone surge at puberty somehow prompts the protein sheath to thicken. This causes the brain to stop sparking and behave more normally.
This did not happen for me. (Nor, it seems, has it happened for Stiles Stilinsky.)
ADHD has a genetic component, and is more prevalent in nomadic societies; there's some evidence in support of the Hunter/Farmer Hypothesis. Essentially, it suggests that ADHD is an adaptive mechanism that is advantageous to hunters in hunter-gatherer societies. (But unhelpful in geometry class.)
What was that you were saying about impulsivity and hyperactivity?
There are three primary... categories, let's say, of ADHD symptom manifestation. Any given person will manifest their own combination of the three. They are:
- inattention (the inability to stick with a task that isn't sufficiently interesting)
- hyperactivity (the inability to sit still)
- impulsivity (some of us have a tendency to make decisions on the spur of the moment rather a lot)
These turn up pretty independently. Each individual will have a different degree of each, or may not have one or two symptoms at all, but if you have even one at disorder levels, it's ADHD.
How do they tell? How does diagnosis work?
Diagnosis for ADHD has stages. It starts with, essentially, a questionnaire, often levelled at your parents if you're a child. (I was an adult, but the diagnosis appointment still required I bring someone else who knew me well, so the psychiatrist could ask someone else about how I seemed, too.)
If your psychiatrist reckons you have ADHD, you then get the fabled prescription: commonly for amphetamine salts, which is what Adderall is and also what I take, so that's what I'll talk about. I was given a trial month. (It allows time to adjust, etc.) After that point there may be adjustments to get you on the right dosage, but the first few weeks are enough for the final diagnostic test, which is the drugs themselves.
If the drugs work like speed is supposed to, if it amps you up and gets you buzzing... you don't have ADHD. ADHD drugs, for ADHD people, provide calmness and focus but not wakefulness. (When I'm short on sleep, I struggle to stay awake when my meds kick in. When, a few months ago, I spent a week in hospital because of a broken leg, that was the only time of day when I could sleep.)
A psychologist I know told me about a patient of his who had serious attention problems. He asked the guy if he'd ever taken speed. Yes, once. What happened then?
Well, he sat down and watched the cricket.
He hated cricket - he thinks it's so boring.
That, folks, is ADHD.
Next, I'll cover what it's like from the inside; how it feels, what it's like to live with, what we do (and don't) do in the course of living as hunters in a world built for farmers.
If you have any questions, post them in comments; I'll try to answer them, and edit this where necessary.