Psychiatry - H.T. Sonnyk 2003

General psychopathology and symptomatology of mental illnesses
Hallucinosis syndrome

Hallucinosis is a state of continuous hallucination driven by an overwhelming influx predominantly of a single type of hallucination. When dominated by an influx of pseudo-hallucinations (whether auditory or visual), the condition is referred to as pseudo-hallucinosis.

Acute hallucinosis is invariably accompanied by pronounced affects of anxiety and/or fear, frequently coupled with hallucinatory delusions, as well as motor agitation and confusion. In chronic hallucinosis, hallucinatory delusions are the most commonly encountered co-occurring disorder. Hallucinoses, particularly acute forms, typically intensify in the evening and at night.

Verbal hallucinosis involves verbal hallucinations or pseudo-hallucinations manifested as a monologue (monovocal hallucinosis), a dialogue, or numerous "voices" forming a "choir of voices" as patients describe it (polyvocal hallucinosis). The content of these verbal hallucinations can be either monothematic or polythematic. True verbal hallucinations—the "voices"—are typically perceived within "auditory reach," such as on the street, in the attic, on the stairs, behind a door, and so on. In contrast, with auditory pseudo-hallucinosis, the "voices" and "thought-conversations" are localized either inside the HEAD or within a space that remains indefinite to the patient.

Acute verbal hallucinosis taking the form of true verbal hallucinations is often accompanied by a distinct imaginative component. Patients describe what they hear with such rich detail that it constantly creates the impression they are actually witnessing rather than Hearing these events (scenelike hallucinosis).

Pseudo-hallucinations may become predominant in chronic hallucinosis. As verbal hallucinosis simplifies, it may be succeeded by verbal illusions and functional hallucinations.

Visual hallucinosis is characterized by an influx of numerous true visual hallucinations. Several distinct types of visual hallucinosis are recognized.

Bonnet's visual hallucinosis occurs in advanced age (individuals over 70–80 years old) in the presence of complete or partial Vision loss. It develops acutely, gradually acquiring a three-dimensional, scenelike quality. Its content typically features people, animals, and scenes from everyday life or nature. Patients act as engaged observers of the unfolding events while maintaining a critical awareness of the hallucinations. This is generally a chronic form of hallucinosis.

Lhermitte's visual hallucinosis (peduncular hallucinosis) arises when the pathological process is localized in the cerebral peduncles (Midbrain). It manifests in the evening and at night as numerous, mobile, miniature or "liliputian," uncolored visual hallucinations (people, animals, birds), with critical insight usually preserved.

Van Bogaert's visual hallucinosis occurs in encephalitis following a period of somnolence. It manifests as numerous, mobile, zooptic visual hallucinations (insects, animals, fish). Progression of this hallucinosis leads to The Development of delirium.

Tactile hallucinosis occurs in advanced, predominantly presenile age. Patients experience itching, prickling, burning, pain, and similar sensations. These pathological sensations are localized in various PARTS OF THE body—on the Skin surface, mucous membranes, or subcutaneously—and are attributed by the patients to the penetration of tiny parasites into these areas (such as beetles, mites, or fleas) or microscopic particles of various substances and objects (sand, Glass, etc.); thus, this hallucinosis is typically combined with delusions. Hypochondriacal and nihilistic delusional ideas may also develop.

Olfactory hallucinosis in its "pure" form is extremely rare. Typically, intense olfactory hallucinations emerge under specific conditions, such as inside the patient's own apartment. Olfactory hallucinosis is frequently accompanied by tactile or sensitive delusions of reference, occurring when patients become convinced that odors (usually unpleasant ones) emanate from their own bodies.

Hallucinoses can be observed across a wide range of psychiatric disorders, both somatically induced and endogenous (such as Schizophrenia). In the latter case, auditory pseudo-hallucinosis is the most frequently encountered presentation.