Which peer‑reviewed studies directly compare Big Five profiles of multiple contemporary populist leaders to Trump?

1. The single most direct, multi‑leader comparison: Nai et al.

The most explicit peer‑reviewed cross‑national comparison that directly measures Trump against multiple contemporary populists is Nai, Martínez i Coma, and Maier’s 2019 Presidential Studies Quarterly article, which reports expert‑rating based Big Five and Dark Triad scores for Trump and places him in rank order among 21 populist leaders and 82 mainstream candidates worldwide, presenting figures and tables that show Trump’s relative extremity on traits such as extraversion, agreeableness, conscientiousness, emotional stability, openness, and the Dark Triad ^{[1] [2]}.

2. Broader populist personality research that includes Trump as a benchmark

A companion strand of peer‑reviewed work asks whether populists as a class differ on Big Five traits and dark traits; West European Politics published a major article in 2019 that finds populists score higher on extraversion and on dark traits like narcissism, Machiavellianism and psychopathy and explicitly references and compares its findings to case studies including Trump ^[3]. That study does not treat Trump as unique but situates him among a pattern of higher dark‑trait scores and particular Big Five configurations attributed to populists ^[3].

3. Pairwise and case‑comparative Big Five work: Trump vs. Chávez

International Studies Quarterly’s 2022 peer‑reviewed article by Thiers and Wehner (and colleagues) performs a detailed personality‑trait comparison of two populist leaders—Donald Trump and Hugo Chávez—linking Big Five differences to divergences in foreign‑policy behavior and explicitly reporting on openness and other Big Five dimensions for both leaders ^[4]. This is a direct, peer‑reviewed comparison, but it is pairwise rather than a multi‑leader ensemble like Nai et al. ^[4].

4. Methods, commonalities, and key limitations across studies

All three peer‑reviewed pieces rely heavily on expert ratings or observational coding rather than self‑report inventories—an acknowledged methodological necessity when surveying leaders ^{[2] [5]}—and the West European Politics work emphasizes that dark‑trait constructs are conceptually distinct from basic Big Five dimensions ^[3]; these choices generate replicable comparative data but also create potential biases from raters and limits on cross‑study metric equivalence ^{[2] [3]}.

5. What the record shows and what it does not

The peer‑reviewed record shows one multi‑leader, cross‑national comparison that places Trump among 21 populists and 82 mainstream candidates (Nai et al. 2019) and at least one rigorous pairwise comparison (Trump vs. Chávez) in ISQ ^{[2] [4]}, while broader populist‑level Big Five analyses appear in West European Politics and related work that contextualizes Trump but do not always present large‑N leader‑by‑leader tables focused solely on Trump comparisons ^{[3] [6]}. What cannot be claimed from these sources is a consensus behavioral diagnosis beyond the reported ratings: differences in sampling frames, rater pools, and whether studies prioritize the Big Five or the Dark Triad mean that synthesis requires careful reading of each paper’s methods ^{[2] [3]}.

6. Takeaway for readers following the claim that “Trump is unique”

The strongest peer‑reviewed evidence available shows Trump scoring as extreme on several Big Five and Dark Triad measures within a comparative set of populist and mainstream candidates (Nai et al. 2019) and highlights both similarities and important differences between Trump and other populists in targeted comparisons like the Chávez study ^{[2] [4]}; nevertheless, the literature remains small, methodologically varied, and dependent on expert assessments, so claims of categorical uniqueness rest on these specific operationalizations rather than on a broad consensus of diverse measurement approaches ^{[2] [3]}.