On March 9, 1965, clinicians and local authorities recorded a cluster of students in a single school exhibiting neurological and somatic symptoms—fainting, hyperventilation, tremors and sensory disturbances—without an identifiable organic cause. The event was later described in psychiatric and public health literature as an instance of contagiously spread conversion symptoms, commonly termed 'contagious hysteria' or mass psychogenic illness (MPI). It attracted attention because of the apparent rapid transmission among pupils, the lack of a confirmable infectious agent or environmental toxin, and the involvement of school routines and social networks in symptom spread. Contemporary reports emphasized the sudden onset among several pupils during class hours, often following an initial case who displayed dramatic symptoms. Local clinicians performed examinations and basic laboratory tests that failed to reveal explanatory pathology. Public health officials investigated environmental factors—air quality, food, and possible chemical exposures—and generally found no consistent physical cause. The working interpretation among many physicians at the time was that psychological and social mechanisms within the school setting accounted for the phenomena: anxiety, suggestion, observational learning and group dynamics leading to conversion of distress into physical symptoms. Scholarly reviews since the 1960s have used this 1965 school outbreak as a case study in MPI because it was documented in medical records and described in professional discussions of conversion disorders and social contagion. However, historians of medicine and public-health researchers caution against calling it the unequivocal 'first' documented case. Accounts of mass psychogenic events date back centuries—instances in medieval convents, the 19th-century Victorian-era 'hysteria' outbreaks, and 19th- and early 20th-century school and factory episodes are documented in archival sources. The 1965 event is better characterized as one of the earlier well-documented school-based outbreaks in postwar North America that entered psychiatric and public-health literature with clinical detail and public-response records. Interpretations of the 1965 outbreak reflect evolving medical concepts. Mid-20th-century clinicians often used psychoanalytic or psychodynamic explanations for conversion symptoms; by the late 20th century, public-health frameworks emphasizing social contagion, stress, and situational triggers became more common. Investigators also recognized the role of media and community reactions: reports of unusual symptoms can amplify attention and anxiety, which in turn may facilitate further cases. Subsequent educational and public-health guidance has aimed at rapid, calm communication, ruling out physical causes, and limiting sensational coverage to reduce the risk of further spread. Methodologically, retrospective descriptions of the 1965 school incident rely on clinic notes, local health reports and later literature reviews; these sources vary in detail and clinical terminology. That variability contributes to differing assessments of how typical this outbreak was relative to other MPI events. Modern researchers apply stricter diagnostic criteria and multidisciplinary investigations—environmental testing, neurology, psychiatry and epidemiology—so historical cases are often re-evaluated in light of contemporary standards. In sum, the March 9, 1965 school outbreak is an important historical example frequently cited in discussions of contagious hysteria or mass psychogenic illness in educational settings. It helped shape subsequent clinical and public-health approaches to similar events, even as historians note earlier and culturally distinct examples of group conversion phenomena. Where precise historical primacy is claimed, scholars advise caution: documentation improves over time, and comparable events predate 1965 in both medical and archival records.