Dr Dorothy Wade is a consultant health psychologist who works with intensive care patients and families, and conducts research on psychological risk factors, outcomes and interventions in intensive care, as an honorary associate professor at University College London. She is currently writing a popular science book about imagination and altered states of mind for Profile Books (Wellcome collection imprint).
A post by Dorothy Wade
In my work as an intensive care psychologist, I frequently hear from patients about the vivid and frightening experiences they undergo. Bombarded by hallucinations and delusions, their visions and thoughts are inescapably real to them. Often involving bizarre elements such as aliens, medieval monks or cannibals, the episodes could be mistaken for scenes of a horror movie (Wade et al 2014).
Marilyn believed there was a baby factory in the hospital basement. She told me the nurses were manufacturing ‘Frankenstein babies’ with disabilities, as a scam to claim welfare benefits. She had seen it for herself, and urged me to go and check the basement. Irene saw puffins jumping on the bed next to hers, shooting blood at her from plastic rifles and laughing day and night. She was scared, but didn’t tell staff or family about the gun-toting birds in case they thought she had lost her mind.
Like thousands of seriously ill people in hospital every day, Marilyn and Irene were suffering from an altered state of consciousness known as delirium. In the aftermath they were terrified, both from the experience, and the belief that they were going mad. Delirium is like imagination on steroids (often literally). There seems to be no limit to the ideas, emotions and extraordinary tales the mind can generate in this state. Delirium in ICU results from brain changes caused by illness, medications (sedatives, opioids or steroids) and a disorientating environment. Although usually temporary, the syndrome may leave people with significant cognitive problems and psychological scars.
While delirium is outside the ordinary experience of many of us, it is just one of our constantly changing states of consciousness. In fact, we spend most of our lives in altered mental states, the most obvious being sleep and dreams. Even when awake, a third to half of our time can be spent in mind-wandering or fantasising. In trying to understand my patients better and explain what might be happening to their minds, I became fascinated by facets of the imagination that emerge in altered states of consciousness.
What causes these shifting states? Can they be classified and studied? For the past year I have been interviewing experts and reading their research on imagination, day-dreams, dreams, hallucinations, delusions, delirium, psychedelic trips, meditation, hypnosis, trance and creativity. I have learned that science has only just begun to take altered states of mind seriously, that states of consciousness are studied in silos, and connections between them are not yet understood.
One question I had about delirium and other altered states is how the mind can spontaneously create mental images and weave them into believable narratives. It is as if the brain contains a fantastical dream machine that generates visions and stories without our conscious effort. Perhaps this is why artists are often attracted to altered states. Many find the early morning post-dream state conducive to creative composition. Writers such as Mary Shelley and Isabel Allende, and film-makers Jean Cocteau and Akira Kurosawa all had ideas that came to them fully-formed in a dream. Other artists receive inspiration in awake hallucinations. Korean writer Juhea Kim had a vision of a tiger while running in a park, and immediately the whole plot of her novel Beasts of a Little Land unfolded in her mind.
While researching dreams, hallucinations, psychedelia and other altered states, I noticed one brain process was frequently mentioned - the default network. In the past 30 years, scientists have shown that anatomically separate areas of the brain are connected to each other to form networks. These brain networks work in harmony to create a variety of states of mind. The networks orchestrate a constant flow of information that arrives from inside and outside the body, as well as thoughts arising in the mind.
The default network is said to play a crucial role in our everyday lives – when our mind wanders or when we imagine, remember or think creatively. It constructs our inner world by linking brain areas related to emotions, memories, mental pictures, selfhood, understanding other people’s perspectives, and predicting our future (Andrews-Hanna et al 2014). Some have called it the ‘imagination network’.
Psychologists define imagination as thinking outside of normal time, place and circumstance (Taylor 2013), while philosophers characterise it as the way we represent things in our mind, without aiming at what they actually are at present (Liao and Gendler 2020). The imagination network, a group of mental processes whose purpose is to dream up alternatives to our present reality, fits in well with these definitions. But some researchers have warned me to be sceptical, because the default network has become the usual suspect to explain any altered brain state.
Certainly it is important to recognise that the default network does not work alone. It collaborates with other brain networks and connectivity between them is key. Another important brain pathway is the attention network, that is activated when we performs tasks. There is a dynamic relationship between the two networks: when activity in the attention network increases, default network activity generally decreases, and vice versa. This seesaw relationship is coordinated by a third player, the control network. In this way, our mind moves smoothly between the external and internal worlds. These accounts are simplified, because scientists are not sure exactly how many brain networks there are or what they all do. The latest research suggests there could be fifteen, including several attention networks and three default networks.
The dynamic framework of thought (Christoff et al 2016) models the interplay of networks as they create different states of mind. For example, in dreaming, the control networks shut down and the imagination network runs riot. When we daydream, our imagination wanders freely, but we stay in touch with the outside world. Creativity depends on cooperation between the imagination and control networks. The dynamic framework is now being updated to explain the effects of psychedelics and meditation.
Reading research on other altered states has made me reflect that delirium is seriously under-researched. Surely delirium is a pressing problem, because it is an involuntary altered state of consciousness affecting the most vulnerable patients. Even the phenomenology is barely known. According to psychiatrists, delirium involves reduced attention and awareness, and problems with mental function that develop quickly (Crone et al. 2025). A few small studies suggest that 50% of patients with delirium have hallucinations or delusions. The hallucinations are usually visual but may be auditory or tactile.
We do not know exactly what happens in the brain during delirium to produce these effects. The sophisticated communication between networks that is needed for the brain to function properly is severely disrupted in delirium. Numerous insults from illness and medication may prevent the brain from switching smoothly between the default and attention networks. An important cause may be inflammation, the body’s response when trying to overcome injury caused by infection, trauma or surgery. As a result of the network chaos, information from the senses or the body’s interior is badly processed and wrongly interpreted by the brain.
Treatment options for delirium are limited. Antipsychotic drugs are often given to delirious patients in ICU, but there is no proof that they work and they have serious side-effects. Holistic methods to address common triggers of delirium such as pain, infection or dehydration are preferred, but there is still little evidence to support them. As a psychologist working in ICU, I was sometimes unsure what our discipline had to offer patients with delirium. Our current dominant cognitive behavioural models (CBT) target thoughts and feelings accessed in a normal state of consciousness. A form of CBT for psychosis that helps people whose sense of reality is altered looked promising, but our trial of those methods did not demonstrate efficacy in ICU patients (Wade et al 2019).
My colleagues and I are going back to basics to map the phenomenology of delirium better, and scope psychological interventions previously used with delirious patients (Shaikh et al, 2024). We hope to develop new delirium therapies to help patients cope with the disturbing experience of the imagination going wild.
References
Andrews-Hanna, J.R., Smallwood, J. and Spreng, R.N. (2014), The default network and self-generated thought: component processes, dynamic control, and clinical relevance. Ann. N.Y. Acad. Sci., 1316, 29-52.
Christoff, K., Irving, Z., Fox, K. et al. (2016). Mind-wandering as spontaneous thought: a dynamic framework. Nat Rev Neurosci, 17.
Crone, C., Fochtmann, L.J., Ahmed, I., et al (2025). The American Psychiatric Association practice guideline for the prevention and treatment of delirium. Am J Psychiatry, 182(9):880-884.
Liao, Shen-yi and Tamar Gendler (2020). Imagination. The Stanford Encyclopedia of Philosophy (Summer 2020 edition), ed. Edward N. Zalta.
Shaikh, M., Wade, D. et al. (2024). Psychological interventions for patients with delirium in intensive care: A scoping review protocol. PloS one, 19(12).
Taylor, M. (2013) Imagination. In P.D. Zelazo (Ed.), The Oxford Handbook of Developmental Psychology (Vol. 1): Body and Mind (pp. 791-831). Oxford University Press.
Wade, D. M., Brewin, C. R., Howell, D. C et al. (2015). Intrusive memories of hallucinations and delusions in traumatised intensive care patients: an interview study. Br J Health Psychol, 20(3), 613–31.
Wade, D. M., Mouncey P.R., Richards-Belle, A., et al. (2019). Effect of a nurse-led preventive psychological intervention on symptoms of posttraumatic stress disorder among critically ill patients: A randomized clinical trial. JAMA, 321(7), 665-675.