When in doubt, blame the mental state of your opposition! That’ll win them over for sure!
HEAVY SARCASM
I believe that's a misinterpretation of the study's intent and implications. The implications of the study appear to be that neuroticism, which is linked to common psychological issues that are often caused by declining socioeconomic conditions, is particularly prone to the types of populist rhetoric that was employed by the Trump and Brexit campaigns. This isn't particularly surprising nor even new; what's new is that they've likely found the strongest correlating psychological "condition" to which right-wing (and perhaps left-wing) populism appeals. They're not blaming anyone's mental state,
per se, but they are noting that neuroticism, which frequently arises in conjunction with local/regional socioeconomic decline, can incline people to support populist campaigns.
