Some of these questions have been studied. When the same criteria are used, prevalence is comparable in Germany, Brazil and other locations. The recognition of the condition is affected by cultural factors but that's true for many conditions.
ADHD by definition is a condition that originates in childhood and persists into adulthood in about 1/2 or more of cases. In adults ADHD is indeed a chronic condition that often responds to amphetamine or methylphenidate treatment. At therapeutic doses, long-term treatment with such agents is generally well-tolerated, but careful monitoring is necessary to assure medication use remains effective and tolerable.
Interestingly, amphetamine has been used for this purpose for nearly 80 years, and methylphenidate for >50 years. Despite the several decades these agents have been employed, nothing more effective has yet been developed.
As I pointed out in my other comment, among adults anyway, the issue is that ADHD is vastly undertreated to the severe detriment of individuals, their families, communities and nation as a whole.
> ADHD by definition is a condition that originates in childhood and persists into adulthood in about 1/2 or more of cases.
Right, and all of this is a question about under what conditions it persists or fails to persist. Does ADHD medication, relative to say behavioral therapy or nontreatment/nonintervention, make it more or less likely that ADHD will persist in adulthood? This is a very important question of those who fear ADHD medication is overused, and may be encouraging ADHD to persist past adolescence.
Very important questions indeed, while there's no complete answer some data is encouraging. Imaging studies, for example, have shown children treated continuously to early adulthood show more robust brain development (white fiber tracts) vs. untreated subjects. Medication treatment is certainly not harmful in that respect and probably helpful.
The role of behavioral therapies is unclear, though practitioners point to instances where that makes a big difference in the outcome. Admittedly it is a hard subject to study systematically given the individualized nature of behavioral treatments.
However research is hardly saying that medication is the only factor. Lately, there is a great deal of attention in the field directed to findings that childhood adversity, e.g., abuse, malnutrition, environmental impoverishment contributes greatly to conditions that resemble ADHD. The implication is clear that reducing the negative impacts of inner-city poverty, etc., would have salutary effects on reducing incidence of psychiatric disorders including ADHD.
In adults, ADHD sufferers with long-term medication treatment show better functioning than untreated peers (matched for age, sex, education, etc.) if less well than unaffected individuals.
Most such studies have used medication therapy as the marker of treatment. So far the contribution of behavioral therapies has been hard to pin down. However, clinical experience is that medication alone is inadequate for adults to improve.
The saying is "pills don't build skills". Indeed, guided behavioral practicing is an essential element of ADHD treatment, though optimized medication treatment can be very useful to enhance neurophysiological infrastructure necessary for normalizing functioning. An individually optimized combination of treatment approaches is most likely to be successful, but hard to determine a priori, thus hard to study experimentally.
I don't believe my response truly satisfies your excellent question, but I'm very glad to know there are people like you who are thinking intelligently about these problems that affect all of us directly or indirectly.
ADHD by definition is a condition that originates in childhood and persists into adulthood in about 1/2 or more of cases. In adults ADHD is indeed a chronic condition that often responds to amphetamine or methylphenidate treatment. At therapeutic doses, long-term treatment with such agents is generally well-tolerated, but careful monitoring is necessary to assure medication use remains effective and tolerable.
Interestingly, amphetamine has been used for this purpose for nearly 80 years, and methylphenidate for >50 years. Despite the several decades these agents have been employed, nothing more effective has yet been developed.
As I pointed out in my other comment, among adults anyway, the issue is that ADHD is vastly undertreated to the severe detriment of individuals, their families, communities and nation as a whole.