Psychiatric diseases alter subjective experience, yet neuroscience mostly studies objective behaviors. Phenomenology, a philosophical tradition examining lived experience, can generate hypotheses about the neurobiological basis of mental illness. Early 20th-century phenomenological psychiatrists made important contributions, but this approach faded with operationalized diagnoses. Recently, clinical-phenomenological research has re-emerged. Using examples from mania and psychosis, the authors show that phenomenological studies can produce fruitful neuroscientific proposals. They advocate integrating phenomenological methods with modern neuroscience, including cross-species research and human subjects work, to move toward a unified understanding of mental illness.
Subjective experience is central to mental illness but has been neglected in empirical psychopathology. The Nested States Model (NSM) offers a framework for constructing detailed phenomenological models by describing subjective experience as a system of nested states. This provides a structured scheme for operationalizing subjectivity, enabling empirical study. The NSM grounds thinking about psychopathological processes around states and their transitions, promising an approach that is close to individual experience, empirically tractable, and aligned with neuroscience research.