It's not a transient condition, like an infection, it develops over time as the brain matures. To call it transient implies that it's fleeting/ephemeral, and having met people diagnosed in their 60's crying because they finally understand why the struggled in life, I saw first-hand that it is not transient.
So, developmental means that it's not present at age 1, but by age 7, it must have become present. Otherwise, we're looking at anxiety or depression or something else. Even those diagnosed with ADHD as adults, one of the stipulations is that they MUST have had symptoms before age 7, though admittedly the DSM versions have changed regarding this point (side note: this is part of the reason the diagnosis is seen as trendy/over-done recently, because subsequent DSM versions have changed it up quite a bit, from what was called minimal brain dysfunction in the 50's to ADD to ADHD these days).
Anyway, the gold standard diagnosis in children is about functional deficits in multiple settings. It's the following: can you remember the items you need every day, can you focus on school, do you lose things, are you disruptive in class, can you keep your seat, are you hyperactive w.r.t. your motor activity? If you have enough deficits, you are diagnosed. These deficits are observed in school, at home, and in as many settings/by as many people as is practical. It's not about expensive scans, which would be impractical and costly. It's all about functional deficits, problems in life. I merely bring up the neurology because it's important for skeptics to understand there is a real, scientifically proven difference in the brains of those with ADHD.
So, developmental means that it's not present at age 1, but by age 7, it must have become present. Otherwise, we're looking at anxiety or depression or something else. Even those diagnosed with ADHD as adults, one of the stipulations is that they MUST have had symptoms before age 7, though admittedly the DSM versions have changed regarding this point (side note: this is part of the reason the diagnosis is seen as trendy/over-done recently, because subsequent DSM versions have changed it up quite a bit, from what was called minimal brain dysfunction in the 50's to ADD to ADHD these days).
Anyway, the gold standard diagnosis in children is about functional deficits in multiple settings. It's the following: can you remember the items you need every day, can you focus on school, do you lose things, are you disruptive in class, can you keep your seat, are you hyperactive w.r.t. your motor activity? If you have enough deficits, you are diagnosed. These deficits are observed in school, at home, and in as many settings/by as many people as is practical. It's not about expensive scans, which would be impractical and costly. It's all about functional deficits, problems in life. I merely bring up the neurology because it's important for skeptics to understand there is a real, scientifically proven difference in the brains of those with ADHD.