Such a great thread. QUESTION: Why do so many people find the PhD experience so

Such a great thread.
QUESTION:
Why do so many people find the PhD experience so tragically stressful, end up in therapy, or worse? What contributes to the stress?
Is there a difference between PhD program models (as in the oxford self directed vs some of the american managed)? Is it just the personnel? Or the subject matter? The workload? The difference in workloads between programs?
Or are we just admitting too many people into the programs without screening them sufficiently (and is it possible to screen people other than by trial and error)?

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