Final answer:
António Egas Moniz popularized the use of frontal lobotomies in the United States between the 1930s and 1950s as a treatment for mental disorders.
Step-by-step explanation:
Between the 1930s and 1950s, the use of frontal lobotomies in the United States was popularized by Portuguese neurologist António Egas Moniz. Moniz developed the procedure in the 1930s and received the Nobel Prize in Physiology or Medicine in 1949 for his work on lobotomies. Lobotomies were initially seen as a treatment for various mental disorders, but they fell out of favor with the introduction of antipsychotic drugs in the 1950s.