Some of the findings of my research on populism are:
Campaigns of populist candidates are substantially more negative and contain much more character attacks than campaigns of non-populist candidates (ref)
Populists score lower on agreeableness, emotional stability and conscientiousness than mainstream candidates (ref)
Populists score higher on extraversion, narcissism, psychopathy and Machiavellianism than mainstream candidates (ref)
Donald Trump has an "off-the-charts" personality profile: very high extraversion and Dark Triad traits (narcissism, psychopathy, Machiavellianism), and very low agreeableness, conscientiousness, and emotional stability (ref)(ref)(ref)
The use of populist appeals (people-centrism, anti-elitism, ..) help driving a greater media coverage (ref)
Gerstlé, J., & Nai, A. (2019). Negativity, emotionality and populist rhetoric in election campaigns worldwide, and their effects on media attention and electoral success. European Journal of Communication, 34(4) 410–444.
Nai, A., and Martinez i Coma, F. (2019). The personality of populists: Provocateurs, charismatic leaders, or drunken dinner guests? West European Politics, 42(7), 1337-1367.
Nai, A., Martinez i Coma, F., and Maier, J. (2018). Donald Trump, populism, and the age of extremes: Comparing the personality traits and campaigning style of Trump and other leaders worldwide. Presidential Studies Quarterly, 49(3), 609–643.
Disagreeable narcissists, extroverted psychopaths, and elections: A new dataset to measure the personality of candidates worldwide. European Political Science, 18(2), 309–334.Nai, A. (2018).
Nai, A. (2018). Fear and loathing in populist campaigns? Comparing the communication style of populists and non-populists in elections worldwide. Journal of Political Marketing. doi: 10.1080/15377857.2018.1491439