It’s correct if they’re talking about multiple different kinds of psychological harm - depression and psychosis, say. Much like if I go and buy both full-fat and semi-skimmed, then I’m buying milks; or if I’m checking the hardness of river and tap samples, then I’m testing waters.
Have we forgotten how to pluralize mass nouns? Back to the 2nd grade with you!
It’s correct if they’re talking about multiple different kinds of psychological harm - depression and psychosis, say. Much like if I go and buy both full-fat and semi-skimmed, then I’m buying milks; or if I’m checking the hardness of river and tap samples, then I’m testing waters.