In recent years, nostalgia has garnered widespread attention across multiple disciplines. In literary studies, it is regarded as a source of aesthetic experience, as exemplified in works such as Genesis, The Odyssey, and In Search of Lost Time. The Routledge Handbook of Nostalgia points out that nostalgia is a global literary phenomenon, providing themes and emotional energy for literary creation. Arnold-Forster's Nostalgia: A History of a Dangerous Emotion traces the semantic evolution of nostalgia over three to four centuries, exploring its developmental trajectory, the mechanisms behind its perception as dangerous, and its influence in fields such as commerce, politics, and psychology. This work re-examines the complexity and multidimensional significance of nostalgia, offering new perspectives for its aesthetic analysis in literary studies.

The Physiological Origins of Nostalgia: A Dangerous Disease

Medical humanities reveal the interplay between medicine and culture, history, and society, demonstrating how medicine evolves alongside social changes. The pathologization of nostalgia serves as a case study of how medicine defines "normal" and "abnormal" to shape social behavior and cognition. In Nostalgia, Arnold-Forster explores its medical origins, tracing it back to the Swiss physician Hofer, who defined the "mental disturbance" caused by intense homesickness as the disease of "nostalgia." Hofer described its symptoms, including persistent sadness and sleep disturbances, and proposed treatments. His diagnosis was influenced by 17th- to 18th-century medical beliefs that emotional fluctuations weakened bodily functions. Arnold-Forster notes that Hofer's research laid the academic foundation for nostalgia, sparking discussions about its geographical distribution. Initially observed in Swiss patients, nostalgia was later considered a potential ailment across Europe. Modern medicine has attempted to reclassify early modern diagnoses of nostalgia but with little success. Hofer's definition constructed nostalgia as a pathological phenomenon with dangerous implications. During the imperial expansions of the 18th and 19th centuries, nostalgia had widespread health impacts, becoming a global epidemic alongside tuberculosis and cholera. Arnold-Forster highlights the severe symptoms of nostalgia among displaced colonial slaves and laborers, even leading to mass suicides. Nostalgia affected slave economies, prompting traders to hire doctors for prevention and treatment. After slavery's abolition, nostalgia persisted among people of color in European colonies. Arnold-Forster cites cases from multiple countries but does not examine the Irish diaspora caused by British colonialism. Ireland's mass emigration, a result of colonial oppression, generated nostalgic narratives. While Arnold-Forster focuses on the nostalgia stemming from the transatlantic slave trade, he omits contemporary Irish migration waves. In mass displacement, individual emotional responses varied—some exhibited severe pathological nostalgia, while others experienced milder homesickness. By the 19th and 20th centuries, affordable rail and steamship travel reshaped perceptions of homesickness. It was no longer solely a threat to health but also a diffuse, everyday sentiment. Initially regarded as a noble virtue, homesickness later clashed with 19th-century ideals of progress, individual mobility, and capitalist-colonial expansion, leading to its dismissal as childish and trivial. Its devaluation was tied not only to nationalist tensions between homeland and new territories but also to its association with childhood emotions.

The Emotionalization of Nostalgia: From Dysfunction to Positive Repair

This section explores nostalgia's shift from a pathological condition to an emotional comfort. By the late 19th century, nostalgia transformed from a disease into an emotion, influenced by psychologists and psychoanalytic schools. Scientists began studying the physiological basis of emotions, advancing affective research and solidifying the modern meaning of "emotion." Nostalgia, as part of this research, evolved from a physiological state to a psychological one. In the early 20th century, psychoanalysis framed nostalgia as cultural anxiety linked to the collective trauma of two world wars. However, postwar political and economic recovery softened psychoanalytic views. By the 1970s, nostalgia was widely seen as benign pathology, and sociologists examined its sociocultural role. By the late 20th century, neuroscience and psychology supported nostalgia's positive effects, revealing its emotional protective function and therapeutic potential for mental health. Nostalgia was redefined as a powerful psychological resource, boosting optimism and creativity. Yet, its reparative qualities do not entirely negate its latent pathological risks. Overall, nostalgia underwent a major transition from dysfunction to healing, with its positive effects enabling its practical applications across diverse fields.

The Political Economy of Nostalgia

Arnold-Forster's essay examines the political economy of nostalgia, noting its contemporary exploitation, with functional value emerging in the 1970s with the nostalgia industry. During the 19th-century imperial era, nostalgia was already weaponized for profit—white nostalgia for homeland or colonial motherlands was glorified, while that of people of color was deemed weak and inferior. In the late 20th century, nostalgia's instrumentalization accelerated, particularly in commerce, urban renewal, and politics. Nostalgia marketing flourished in TV ads, leveraging personal or historical nostalgia to drive consumer behavior. It also became a workplace management tool, fostering belonging and retention. Postmodern capitalist societies exploit nostalgic environments to lure emotional consumption, though such historical nostalgia is often imagined. Politicians harness nostalgia, as seen in Trump's U.S. presidency and Brexit, where it permeated political life. Arnold-Forster argues that nostalgia reflects shifts in sociopolitical culture, with its "danger" rooted in its political-economic utility, making it a convenient tool for various agendas.