Major depression is a prevalent mental disorder that leads to persistent negative mood and tremendous suffering in affected individuals. However, the biological realization of this disorder and associated symptom clusters remain poorly understood. Recently, phenomenological accounts of major depressive disorder and contributions to the emerging predictive processing account have provided valuable insights into the phenomenological and neuro-functional components that lead to manifestations of major depressive episodes. The purpose of this paper is to weave together these different strands of research to (...) develop a predictive processing account of major depressive disorder. In doing so, I will relate personal-level descriptions of associated phenomenal experiences to a sub-personal-level predictive processing account of the functional realization of major depression. I will argue that pervasive symptoms of the disorder, which include a diminished sense of agency, fatigue, social withdrawal, and rumination, are integrated by existential feelings of loss and impossibility. These phenomenal experiences, I will argue, are associated with dysfunctional processes of prediction error minimization, which are characterized by an overall decrease of the causal contributions of active inference and by distorted precision estimates. The emerging account promises to contribute to a better understanding of the complex processes that give rise to depressive experiences. (shrink)

First-person reports of Major Depressive Disorder reveal that when an individual becomes depressed a profound change or ‘shift’ to one’s conscious experience occurs. The depressed person reports that something fundamental to their experience has been disturbed or shifted; a change associated with the common but elusive claim that when depressed one finds oneself in a ‘different world’ detached from reality and other people. Existing attempts to utilise these phenomenological observations in a psychiatric context are challenged by the fact that this (...) experiential ‘shift’ characteristic of depression appears mysterious and resists analysis in scientific terms. This paper offers a way out of this predicament. The hypothesis proposed is that when an individual becomes depressed, the individual departs from a state of ordinary wakeful consciousness and enters a distinctive global state of consciousness akin to dreaming and the psychedelic state. After unpacking and motivating this hypothesis in the context of research in consciousness science, I outline two of its important implications for the neurobiology of depression and psychedelic psychiatry. The upshot is a promising and conceptually well-motivated hypothesis about depression which is apt for empirical uptake and development. (shrink)