Why was ADHD underdiagnosed or misunderstood in previous generations?

This is a really good question, and the short answer is that our understanding was limited, not that people weren’t struggling. For a long time, ADHD was narrowly defined. It was seen mainly as a childhood behavior problem, especially in young boys who were hyperactive and disruptive in classrooms. If you were quiet, inattentive, anxious, high achieving, or internalizing your struggles, you were unlikely to be noticed. Many girls, thoughtful kids, and academically capable students were completely missed. We also didn’t understand the adult presentation. ADHD was believed to be something children outgrew, rather than a lifelong neurodevelopmental condition. Adults who struggled were labeled as lazy, disorganized, anxious, or “not living up to their potential,” rather than being assessed. Cultural expectations played a role too. Previous generations often had more external structure, clearer roles, and fewer cognitive demands. That structure can mask ADHD. When life is simpler or more routine, symptoms don’t stand out as much. As demands increase, cracks become visible. There was also stigma. Mental health wasn’t openly discussed, especially not in adults. People learned to push through, compensate, or suffer quietly. Many did incredibly well outwardly while paying a heavy internal cost. What’s happening now isn’t an explosion of ADHD. It’s better recognition. We have better research, better language, and a broader understanding of how ADHD actually looks across ages, genders, and life contexts. So many adults weren’t missed because ADHD didn’t exist. They were missed because the system wasn’t looking for them yet.