In considering why mental illness is seemingly far more widespread than in pre-modern times, less might be said for improvements in diagnosis and rather more about the relationship between the individual and society. 

While our understanding of the mind is far greater than at any other time in human history and the capacity to treat is vastly enhanced, merely being better at these things does not explain the increased prevalence of a range of apparent psychological disorders. Why are so any people “sick” or incapacitated and what does this say about modernity. 

My own thoughts follow a long line of talented and erudite theorists such as Sartre, Camus, Kierkegaard and Nietzsche, all of whom commented on an aspect of the modern that could present a crisis for the individual. The decline of religious belief, the rise of science and the ascent of the rational, the alienating effects of work in cities, the dislocation of humankind from the natural world, the rise and triumph of consumer capitalism, and so forth, have exerted pressures that are unique in the evolution of the species.

Essentially, it boils down to the finding of meaning in one’s life, meaning that was supplied in abundance for our ancestors. We might find such meaning primitive or foolish today but the lack of meaning, the confusion and dissatisfaction and moral paralysis that has ensued, are a seeding ground for mental illness and disintegration.