A note by Sophia
“Extrathyme” and “introthyme” are alternative terms used to refer to people who are, respectively, extraverted or introverted in the socionics sence. These terms were coined by Aushra Augusta in her work On the Dual Nature of Humanity.
We replaced Jung’s terms “extraverted” and “introverted” with the now common “extravert” and “introvert,” although we believe that the terms “extrathyme” and “introthyme,” made by analogy with Kretschmer’s terms “schizothyme” and “cyclothyme,” would be even more appropriate. We believe so due to the fact that the terms “extravert” and “introvert” became ambiguous after the works of Eysenck, whose tests inspired a trend to call every sociable person an extravert and every withdrawn person an introvert.
Aushra Augusta, On the Dual Nature of Humanity
In turn, the terms “schizothyme” and “cyclothyme” were coined by Ernst Kretschmer in his book Physique and Character to refer to two distinct temperaments. Augusta’s works seem to suggest that the schizothymic temperament corresponds to socionics rationality, and cyclothymic – to irrationality (see Socion).
Classic Socionics 