The Future of Psychoses as Seen from the History of its Evolution

Abstract

Reflecting on the history of psychoses reveals several trends in psychiatry’s approach to this difficult disease. The field initially took a symptom-based categorical approach in the 18th to the early19th century; in the late 19th century, Kraepelin unified diverse categories into the unitary concept of dementia praecox, and separated it from manic depressive insanity. While this distinction has persisted ever since, the last 5 decades witnessed a focus on operationalizing symptomatic criteria continuing into the current Diagnostic and Statistical manual (DSM) classification. While reliability has improved somewhat, the question of validity of the psychosis diagnosis remains elusive. Recent approaches attempt to investigate disease dimensions across diagnoses, characterize heritable biomarkers, and identify translational domains of psychopathology across molecular, cellular, circuit, and behavioral units of analyses. Such efforts may help deconstruct current symptom-based phenotypes and allow reconstruction of disease constructs that may better map to etiology, pathophysiology and treatment response. Studying the history of the concept of psychosis affords a unique vantage point to better understand the challenges associated with this current thinking and how such may guide today’s work in creating tomorrow’s new definition of psychoses, probably better grounded in neuroscience.