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Conference Proceeding

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American Politics | International Relations | Leadership Studies | Other Psychology | Other Public Affairs, Public Policy and Public Administration | Personality and Social Contexts


This paper presents the results of an indirect assessment, from the conceptual perspective of personologist Theodore Millon, of the personality of Donald J. Trump, 45th president of the United States, based solely on personality dynamics revealed by his political behavior in office.

Psychodiagnostically relevant data were collected from biographical sources and media reports of Trump’s postinaugural political behavior from January 20, 2017 until July 2020 and synthesized into a personality profile using the Millon Inventory of Diagnostic Criteria (MIDC), which yields 34 normal and maladaptive personality classifications congruent with DSM-III-R, DSM-IV, and DSM-5.

The personality profile yielded by the MIDC was analyzed in accordance with interpretive guidelines provided in the MIDC and Millon Index of Personality Styles manuals. Trump’s primary personality patterns were found to be Ambitious/self-serving (bordering on exploitative), Dominant/controlling (bordering on aggressive), and Outgoing/gregarious (bordering on impulsive), infused with secondary features of the Dauntless/dissenting pattern. There is suggestive, equivocal evidence of incipient Distrusting/suspicious and Erratic/unstable tendencies emerging during Trump’s time in office.

Ambitious individuals are bold, competitive, and self-assured; they easily assume leadership roles, expect others to recognize their special qualities, and often act as though entitled. Dominant individuals enjoy the power to direct others and to evoke obedience and respect; they are tough and unsentimental and often make effective leaders. Outgoing individuals are dramatic attention‑getters who thrive on being the center of social events, go out of their way to be popular with others, have confidence in their social abilities, tend to be impulsive and undisciplined, and become easily bored — especially when faced with repetitive or mundane tasks. Dauntless individuals tend to flout tradition, dislike following routine, sometimes act impulsively and irresponsibly, and are inclined to elaborate on or shade the truth and skirt the law.

Trump’s executive leadership style in office has been bold, competitive, and self-assured (i.e., ambitious); tough and directive (i.e., dominant); impulsive and undisciplined (i.e., outgoing); and disruptively tradition-defying, with an inclination to shade the truth and skirt the law (i.e., dauntless).


The research was conducted at the Unit for the Study of Personality in Politics (USPP), a collaborative faculty–student research program in the psychology of politics at St. John’s University and the College of St. Benedict in Collegeville and St. Joseph, Minnesota, directed by Aubrey Immelman, Ph.D., associate professor of psychology, who specializes in the psychological assessment of presidential candidates and world leaders.

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