Dream-Like Change of Consciousness
A dream-like change of consciousness is a lowering of the level of consciousness in which a person becomes disoriented for time and place, though not for person, and loses the ability to distinguish their own mental images from genuine perceptions, so that vivid imagery takes on the full, convincing quality of something actually being seen or heard. The outstanding feature is usually vivid, often frightening visual hallucinations, most classically of small animals, alongside disordered thinking with the same qualities seen in ordinary dreaming.
This has traditionally been recognised as the core presentation of acute delirium, and milder degrees of the same underlying process, sometimes loosely called a toxic confusional state, can also occur, with the disturbance of consciousness characteristically worse at night and improving somewhat by morning.
Also known as
- Toxic confusional state
- A term sometimes used for a milder variety of this pattern, but flagged as somewhat unsatisfactory since it is used inconsistently by different practitioners.
Recognition features
- Disorientation for time and place, but orientation for person is preserved
- Vivid visual hallucinations, classically of small animals, often accompanied by fear or terror, though occasionally, when Lilliputian in character, accompanied instead by pleasure
- The person cannot reliably distinguish their own mental imagery from genuine perception, so that imagined content is experienced with the full force of something actually present
- Disordered thinking with a dream-like quality, and additional hallucinations of touch, pain, electric sensations, muscle sense, or balance may also occur; the person is often fearful and may misinterpret others' actions as threatening
Eliciting it at interview
- Assess orientation for time, place, and person specifically, noting the characteristic preservation of orientation for person even when time and place are lost
- Ask gently and specifically about visual experiences, including any sense of seeing animals or small creatures, and about the person's emotional reaction to them
- Note whether the disturbance fluctuates over the course of the day, since a characteristic worsening at night with some improvement by morning is a useful clinical clue
Distinguishing features
- Differs from lowering of consciousness in the presence of prominent hallucinations, illusions, and restlessness, none of which are typical of the more benumbed, torpid picture
- Differs from a primary psychotic hallucination in its close association with disorientation and its characteristic dream-like, imagery-based quality rather than occurring with clear consciousness
- Occupational delirium, in which the person carries out familiar actions from their usual trade or occupation, is a specific and distinctive pattern that can occur within this broader picture
Common misconceptions
- That a person experiencing this state can always tell that their vivid visual experiences are not real; the defining feature is precisely the loss of this distinction, so the hallucinations are experienced with full conviction
- That the term 'toxic confusional state' has one settled, agreed meaning; the book itself flags this as an unsatisfactory term used inconsistently across different practitioners
Related phenomena
Disturbance of Consciousness · Occupational Delirium · Visual Hallucination
Practice this
Recovering from a severe chest infection, a 79-year-old man becomes convinced that small rodents are scurrying across his hospital bedsheets at night, reacting with genuine terror and swatting at them repeatedly. During the day he is calmer, though still unable to say what day it is, and he recognises his wife immediately whenever she visits. What is this presentation? · A 68-year-old woman recovering from surgery insists there are insects crawling on the wall and becomes distressed trying to brush them off, entirely convinced they are real. She cannot say what day it is but greets her son by name the moment he enters. A nurse tells you she was calm and lucid an hour ago. Before revealing the answer: what is this presentation, and what does the fluctuation over the last hour tell you? · Two elderly patients each show some disturbance of consciousness following an acute physical illness. Before revealing the answer, decide what single feature best separates a dream-like change of consciousness from lowering of consciousness. · A patient shows disorientation with an altered level of consciousness. Before revealing the answer, decide what distinguishes restriction of consciousness from a dream-like change of consciousness. · You are assessing an elderly patient overnight staff describe as 'confused and frightened.' Before revealing the answer, decide how you would assess specifically for a dream-like change of consciousness. · Explain why a patient experiencing a dream-like change of consciousness cannot simply be reassured that their hallucinations 'aren't real.'
Illustration
Recovering from a severe chest infection, a 79-year-old man becomes convinced that small rodents are scurrying across his hospital bedsheets at night, reacting with genuine terror and swatting at them repeatedly, while during the day he is calmer though still unable to say what day it is, and he recognises his wife immediately whenever she visits.
References
- Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 9, 'Disorders of Consciousness'.