Background: Adult ADHD has increasingly become a focus in adult psychiatry. Despite well-established diagnostic criteria and specific therapeutic approaches, contemporary discussions often dismiss ADHD as a "fad." This study examines Carl Gustav Jung's 1904 concept of "manic mood" and its potential alignment with the modern understanding of ADHD in adults. Objective: The aim of this paper is to investigate and discuss whether Jung's concept of "manic mood" can be considered part of the intellectual history of adult ADHD. Method: Jung's concept of "manic mood" is analyzed and presented using the literary-historical method of "close reading," placing the analysis within the context of the early 20th-century discussion of "chronic-manic concepts." This analysis is compared with the current diagnostic criteria for adult ADHD. Results and Conclusion: Jung's concept of "manic mood," described in 1904, has clear parallels to diagnostic criteria used for adult ADHD. It is conceivable that the patients presented by Jung would be diagnosed with adult ADHD today. Jung's work fits into the discussion of "chronic-manic concepts" of the early 20th century and thus makes a relevant original contribution to the nosological-diagnostic classification of forms in the spectrum of ADHD-affective disorders-personality disorders. The parallel between Jung's disease construct of "manic mood" and the current view of ADHD supports our hypothesis that the adult form of ADHD represents a consistent disease phenomenon and should therefore not be degraded as a "fad."