For something specifically like dementia, I'd recommend reading Daniel George and Peter Whitehouse. They both go into how dementia rates have fallen over the past few decades, despite the silver bullet still not being available to beat dementia/Alzheimer's. They're heavily critical of the desire to look for this silver bullet, when there is evidence that social policies geared towards the collective well being of any given populace have a noticeable effect on lowering rates of cognitive decline.

They're super critical of neoliberalism and the marketization of nearly all aspects of Western life. They delve into how programs like the New Deal and others which allowed for greater access to education and healthcare had an outsized effect on slowing down mental decline. They mention the reduction of lead in gasoline as an example of something which helped tremendously, and also mention how lead in water pipes remains an issue. Recently I heard an interview with both of them, and they are seemingly becoming more and more blackpilled. They were cautiously optimistic when they saw the temporary revival of some social programs during the pandemic, hoping that it would lead to societal reset as it relates to the state becoming more involved in the welfare of the people. Unfortunately that hasn't happened, and we might soon go back to our regularly scheduled programming.