From Perception to Thought: A Phenomenological Approach to Hallucinatory Experience

The very presence of hallucinations raises puzzling and fascinating questions about reality … However, my real questioning did not fully occur until the voices started, which was once again a gradual process … When the voices occurred, I perceived them as omnipotent and omniscient … To me, auditory-verbal hallucinations are the result of thought processes of which I am unaware.

Humpston 2014

The horizon and the conceptual landscape of psychosis research have changed dramatically over the past decades.¹ First, the identification of “meaningful” similarities and points of rarity across diagnoses is catalyzing a heuristic deconstruction of clinical syndromes into salient psychopathological domains.^2–4 Second, new transnosological frameworks have been introduced (eg, the clinical staging model⁵), enriching the traditional categorical vs dimensional debate.

However, crucial foundational aspects of psychiatric investigation, such as the nature and statute of psychiatric sign and symptoms,⁶ remain largely unaddressed. This is particularly evident in the case of the definition of hallucinatory experiences, allegedly a prototype of psychotic mental states. In the current issue, Waters and Fernyhoug’s systematic review⁷ raises nontrivial reservations on the value of hallucination features in terms of differential diagnosis. While possibly a byproduct of descriptive blind-spots in available assessment tools, their findings question the pathognomonic value of hallucinations, that overall appear as relatively nonspecific symptoms (and—to some extent—not even indicative of a psychotic state).

By contrast, phenomenological psychiatry considers hallucinations as psychotic end-phenomena arising from a global transformation of consciousness (ie, the background structure or medium organizing the flow of subjective experience). It is the nature of such underlying change in the structure of experiencing that confers specificity to “surface-level” hallucinatory phenomena. For example, multiple scenic hallucinations with kaleidoscopic quality accompanying the oneiroid narrowing of consciousness differ from blossoming geometric hallucinations occurring in psychedelic states. The difference, however, is not primarily in some extrinsic perceptual features of the putative hallucinatory object (eg both are visual, vivid and generally externalized), but rather in the type of qualitative transformation of consciousness (eg, clouding vs synesthetically expanded consciousness) from which they emerge. Such transformation brings about changes in the lived experience of time, space, self, and immediate immersion in the world, which inform hallucinatory phenomena as well as other symptomatic manifestations.

Therefore, understanding (and describing) the ongoing transformation of the field of consciousness (ie, in phenomenological terms, the invariant condition of possibility for a certain experience to emerge) is the first step to characterize the symptom generating trajectories leading to full-blown hallucinations. It is the nature of such generative trajectory, rather than the descriptive features of hallucinations, that confers diagnostic specificity. In this sense, the genesis of auditory hallucinations in schizophrenia spectrum disorders is not commensurable to the one in Lewy body dementia, and hence any feature similarity between the 2 auditory hallucinations is of dubious clinical and research utility.

Clearly, this level of investigation, which amplifies the resolution power of psychopathological description, can empower the identification of target phenotypes for etiological research and differential diagnosis.⁸

Beyond the Percepto-Centric Approach: A Phenomenological Perspective

From a clinical–phenomenological stance, hallucinations are first and foremost salient episodes that primarily affect the ongoing flow of subjective experience (ie, the stream of consciousness). That is, their essential core is not their material affinity with perceptual processes but rather their appearing in the phenomenal realm of lived experience “as something quite new … alongside real perceptions.”^9(p66)

Unfortunately, the mainstream definition of hallucinations (eg, DSM V^(p822): “a perception-like experience with the clarity and impact of a true perception but without the external stimulation of the relevant sensory organ”), enforcing the surface analogy with abnormal perceptions could be clinically and conceptually misleading.

That is, it is at odds with many experiential reports from help-seeking people and prejudicially orients etiopathogenetic research toward presumed perceptual errors in the processing of external sensory stimuli.^10,11

Indeed, as several first personal accounts indicate (see refs.^12,13), hallucinations are experienced in a more nuanced, rich, and dynamic way, than the prevailing behavioristic-operational lexicon of psychopathology seems to capture. Such descriptions suggest that what is experientially at stake—at least in the initial emergence of hallucinations—is a sort of dissolution of certain structural features of consciousness.^8,10,14,15

In this respect, perceptual-like characteristics of hallucinations (eg, sensorial modality, spatial location, intensity) are rather contingent upon the phenomenal features of the morbid state of consciousness (eg, delirium/acute confusional state, psychedelic consciousness, predelusional atmospheric mood [wahnstimmung], manic acceleration, melancholic stagnation, or schizophrenic hyperreflexivity), which confer an organized structure to lived reality (ie, a characteristic gestalt).

Thus, classifying hallucinations on the basis of their eminent perceptual characteristics without grasping their experiential structure, might lead to a redundant proliferation of descriptors with modest discriminant value.⁷

Phenotyping Psychotic Consciousness: The Case of Auditory Hallucinations Schizophrenia Spectrum Disorders

A recent extensive survey by Woods et al¹⁶ rediscovered what was taken for granted by prominent clinicians such as Kraepelin and Bleuler almost a century ago. That is: even auditory verbal hallucinations (aka “voices”) are not necessarily experienced as strictly acoustic events, but are often endowed with prominent thought-like qualities and often articulate themselves in coenesthesic phenomena as well. The core psychopathological organizer is a loss of mineness and privacy of the stream of consciousness, that only as extreme end-phenomena culminates in the schneiderian feeling of being at the “center of a network of disembodied voices.”^17(p161) Such transitions, which have been described in systematic way^18–22 intervene along a coherent sequence leading from non-psychotic experiential precursors to psychotic phenomena (such as auditory hallucinations) through a series of progressive experiential changes of increasing severity. Those include: basic disturbances of the thought stream (eg, thought interference, thought block, pressure of thought), progressive depersonalization with intensified experience of thought spatialization, alienation, and/or autonomization of the interior dialogue (eg, repeated inner “self-instructions,” “self-comments,” and/or “self-conversations” become progressively sonorized, automatized, and interfering), loss of the ego-boundaries eventually culminating in “omnipotent and omniscient” alien voices and/or transitivistic experiences. In this respect, verbal hallucinations in schizophrenia resemble cognitive-noetic phenomena (ie, contents of consciousness that become abnormally reified, spatialized, sensorialized, and ultimately externalized) rather than abnormal “perceptions without an object.”

The translational potential of these phenomenological insights has been recently condensed into reliable assessment tools (eg, BSABS, SPI-A/CY, EASE),²¹ which allow a fine-grained experiential mapping of such psychopathological sequences.

Phenomenology in Translation: A Research Roadmap

Hallucinatory phenomena entail an overarching transformation of the stream of subjective experience that escapes the conventional percepto-centric definition. Phenomenological approach provides a parsimonious, person-centered way of understanding the experiential development of hallucinations, discerning their emergence from the background changes in the structure of consciousness. Such approach could help identifying better target-phenotypes for the search of neurobiological correlates of psychotic mentation. Future empirical research might capitalize on phenomenological psychopathology to:

1. get a richer, experience-close mapping of the formation of psychotic phenomena;

2. increase the resolution power of assessment tools, particularly in developmentally sensitive phases (eg, adolescence) and putatively pluripotential risk states (eg, attenuated psychosis);

3. identify core features and points of rarity between psychiatric disorders, eg, within the area of psychotic disorders (eg, schizophrenia²³ and bipolar spectrum²⁴).