When we look at poor societies, or even much of Western Europe >100 years ago, we see vast swaths of the population with stunted physical growth suffering from preventable and treatable nutrient deficiencies. E.g., currently around 50-70% of people in Africa are anemic, in large part due too deficiencies in dietary iron [1].
In the same way, I'm wondering if at some point in the not-too-distant future we'll look back to today and see the mental health of whole populations as "malnourished", the psychological equivalent of mean population height being 5 feet tall.
Alternatively, perhaps it's currently being over-diagnosed.
There seems to be a trend toward medicalizing behavior, emotion, and personality traits, including those that fall within the normal range of human variation, or that may actually be healthy responses to external stimuli.
Is it really reasonable to describe 'ADHD' and mild forms of depression as mental illness?
Mental illness may have been formerly under-diagnosed.