NEW YORK — Theodore Millon, a psychologist whose theories helped define how scientists think about personality and its disorders, died Jan. 29 at his home in Greenville Township, N.Y. He was 85.
The cause was complications of heart disease .
Dr. Millon learned about the oddities of personality firsthand by wandering the halls of Allentown State Hospital, a mental institution, after being named to the hospital’s board in the 1950s as a part an overhaul effort in Pennsylvania.
A young assistant professor at nearby Lehigh University at the time, he “frequently ventured incognito through the hospital,” he wrote in an essay in 2001, “at times clothed in typical hospital garb overnight or for entire weekend periods, conversing at length with patients housed in a variety of acute and chronic wards.”
At the University of Illinois in the 1970s, he began to think and write more deeply about the patterns underlying specific character types that therapists had described: the narcissist, with fragile, grandiose self-approval; the dependent, with smothering clinginess; the histrionic, always in the thick of some drama, desperate to be the center of attention.
By 1980, he had pulled together the bulk of the work on such personality disorders, most of it descriptive, and turned it into a set of 10 standardized types for the American Psychiatric Association’s third diagnostic manual.
Along the way he developed the Millon Clinical Multiaxial Inventory, which became the most commonly used diagnostic assessment for personality problems. It is still widely used.
Dr. Millon was born in New York. After graduating in 1950 from City College of New York, he received a doctorate from the University of Connecticut in 1953.