Study tracking mental health after bariatric surgery:

The prevalence difference in filled psychiatric drug prescription was highest 10 years after the matched index date (20·4%; 15·9–24·9), when 171 (36·5%) of 469 surgery patients and 739 (16·0%) of 4607 matched adolescents filled a psychiatric drug prescription.

TL;DR: psychiatric diagnoses & prescriptions were more common in the cohort before bariatric surgery and a lot more common after. People were feeling super bad.

The chickens & eggs get tangled up when trying to view larger trends around this issue—perhaps there are feedback loops?