COVID-19 can trigger hallucinations through several distinct pathways, from direct effects of the virus on the brain to the inflammatory storm it unleashes to the social isolation that accompanied the pandemic. The experience ranges from phantom smells to vivid visual scenes to hearing voices, and it can appear during acute infection, weeks later in long COVID, or even as a side effect of treatments like corticosteroids. Understanding which pathway is responsible matters, because the right response depends on the cause.
What the Hallucinations Actually Look Like
The word “hallucination” covers a wide range of experiences in COVID patients, and the type matters clinically. A systematic review of published case reports found that auditory hallucinations were the most frequently reported psychotic symptom, appearing in roughly three-quarters of cases. Visual hallucinations were less common but still well documented, and tactile hallucinations (feeling things that are not there) appeared occasionally.1PubMed Central. Psychosis during the COVID-19 pandemic: A systematic review of case reports and case series In some cases, patients heard commanding voices; in others, they saw deceased family members or felt insects crawling on their skin.
A study of rehabilitation patients hospitalized with COVID found that about one in five experienced hallucinations during their stay. Seven of the eight affected patients had visual hallucinations consistent with a condition called peduncular hallucinosis, where vivid, often colorful visual scenes appear, sometimes alongside sounds or touch sensations. The themes patients described tended to cluster around comfort-seeking, fear, and seeing people who had died.2Archives of Rehabilitation Research and Clinical Translation. Complex Hallucinations in Hospitalized Rehabilitation Patients With COVID-19 These were not fleeting impressions. Patients recalled them clearly afterward, and many found them distressing.
Phantom Smells Are Their Own Category
One form of hallucination stands apart from the rest and is far more common: phantosmia, the perception of smells that are not there. While most people know that COVID can steal your sense of smell, fewer realize that it can also create entirely false ones. Patients report smelling smoke, chemicals, garbage, or rotting food with no source. These phantom odors often set in during the recovery phase rather than at the height of illness.
A large study tracking olfactory dysfunction after COVID found that phantosmia was more likely when smell loss came on gradually rather than all at once, when it fluctuated rather than stayed constant, and when it was partial rather than total. Women were significantly more likely to experience phantom smells than men.3PubMed Central. Phantom smells: a prevalent COVID-19 symptom that progressively sets in The pattern suggests that phantosmia emerges as the olfactory system tries to repair itself. Damaged nerve cells send garbled signals to the brain, and the brain interprets them as real smells. For most people, the phantom odors fade over weeks to months, but a minority deal with them for much longer, and early attention to lingering smell problems may help prevent that.4PubMed Central. Short duration phantosmia changes in a post-COVID-19 patient in Bangladesh
Phantosmia is qualitatively different from auditory or visual hallucinations. It does not involve psychosis, does not indicate a psychiatric disorder, and usually resolves on its own. If you are smelling burnt toast that nobody else smells three weeks after COVID, that is almost certainly your olfactory nerves recovering, not a sign that something is going wrong with your mind. The distinction matters because the two categories call for very different levels of concern.
How the Virus Affects the Brain
The mechanisms behind COVID-related hallucinations are not fully settled, but several lines of evidence point to inflammation as a central driver. SARS-CoV-2 can disrupt the blood-brain barrier, the tightly sealed lining that normally keeps pathogens and immune cells out of brain tissue. When that barrier breaks down, it triggers a cascade of inflammatory molecules and immune-cell activation inside the brain itself.5Frontiers in Cellular Neuroscience. Alteration of the blood-brain barrier by COVID-19 and its implication in the permeation of drugs into the brain The resulting neuroinflammation can disrupt the normal functioning of brain regions involved in perception, mood, and thought.
Brain imaging studies have confirmed that this disruption is not theoretical. PET scans of patients with COVID-related encephalopathy showed a consistent pattern of reduced metabolic activity in the frontal cortex, the anterior cingulate, the insula, and the caudate nucleus.6PubMed Central. The cerebral network of COVID-19-related encephalopathy: a longitudinal voxel-based 18F-FDG-PET study Several of these regions are directly involved in filtering sensory information and distinguishing real perceptions from internally generated ones. When they are not working properly, hallucinations become more likely.
There is also growing evidence that the immune response to COVID can go haywire in a specific and troubling way: the body starts producing antibodies that attack its own neural tissue. Researchers have found that COVID patients with neuropsychiatric symptoms are more likely to carry these neural autoantibodies than control subjects, and that the antibodies appear to be produced within the central nervous system itself rather than just leaking in from the bloodstream.7PubMed Central. Psychiatric Symptoms in Acute and Persisting Forms of COVID-19 Associated with Neural Autoantibodies Animal studies have shown that SARS-CoV-2 infection in the brain stimulates local antibody production, and a subset of those antibodies turn out to be self-reactive.8Cell Reports Medicine. Distinct immunological landscape of CSF and PBMCs in individuals with COVID-19 with neurological symptoms This autoimmune process could explain why some patients develop psychiatric symptoms days or weeks after the acute infection clears, when the virus itself may no longer be detectable.
When the Treatment Is the Problem
Not every hallucination during COVID comes from the virus. Corticosteroids like dexamethasone and methylprednisolone became standard treatments for severe COVID pneumonia, and they are well known to cause psychiatric side effects. In one documented case, a patient developed acute psychosis with hallucinations and paranoid delusions after just two days of intravenous methylprednisolone. Reducing the steroid dose and adding an antipsychotic medication led to a rapid response: hallucinations stopped within 24 hours, and the remaining psychotic symptoms resolved completely within days.9PubMed Central. Acute psychosis following corticosteroid administration for COVID-19 and Respiratory Syncytial Virus infection: A case study
Steroid-induced psychosis is a recognized phenomenon that predates the pandemic. What makes it tricky in COVID patients is that it can be hard to tell apart from virus-driven psychiatric symptoms, especially when both are happening at the same time in a severely ill person. The practical difference is important: if the steroids are causing the problem, adjusting the dose can fix it quickly. If the virus itself is driving the symptoms, steroids might actually help by reducing neuroinflammation. Getting the diagnosis wrong means either continuing a drug that is making things worse or withdrawing a drug that is actually needed. Clinicians looking after COVID patients with new-onset hallucinations have to consider the timing carefully, since symptoms appearing shortly after starting or increasing corticosteroids point strongly toward a medication side effect.
Hallucinations That Arrive Late
Some patients develop hallucinations or other psychotic symptoms not during acute COVID, but weeks afterward, as part of long COVID. One case report describes a woman with no psychiatric history who began experiencing mania and possible psychotic features several weeks after her initial infection. She slept only one to four hours a night, journaled a hundred pages in two days, believed a demonic power was tormenting her mind, and swung between laughing and crying spells. These symptoms lasted about eight days.10PubMed Central. Acute Onset of Mania and Psychosis in the Context of Long-COVID: A Case Study
Late-onset psychiatric symptoms present a diagnostic challenge because the connection to COVID is not always obvious. By the time hallucinations or psychosis appear, the respiratory illness may have fully resolved, and neither the patient nor the clinician may think to link the two. A systematic review and meta-analysis tracking neuropsychiatric symptoms after COVID found that most studies followed patients for an average of about 77 days, with some tracking symptoms beyond 12 weeks.11Brain Communications. Persistent neuropsychiatric symptoms after COVID-19: a systematic review and meta-analysis The autoimmune mechanism described earlier may play a role here: the body’s misdirected immune response can simmer long after the virus is gone.
Historically, respiratory pandemics have left neuropsychiatric aftershocks. The 1918 influenza pandemic was followed by a wave of encephalitis lethargica that, in some patients, eventually progressed to a form of parkinsonism. Researchers have drawn parallels between that episode and the emergence of long COVID as a new chronic post-viral condition, suggesting that we may still be in the early stages of understanding the full neurological fallout of SARS-CoV-2.12PubMed Central. “Spanish flu,” encephalitis lethargica, and COVID-19: Progress made, lessons learned, and directions for future research
Who Is More Vulnerable
Certain groups face a higher risk of COVID-related hallucinations, and some of the risk has nothing to do with the virus directly. People with Alzheimer’s disease living in care homes showed increased hallucinatory experiences during pandemic lockdowns compared to before. The explanation appears to be largely environmental: the drop in social contact, the loss of structured activities, and the physical separation from family members reduced sensory stimulation and increased loneliness, creating conditions that favor hallucinations in people whose brains are already vulnerable.13PubMed Central. Hallucinations and Covid-19: Increased Occurrence of Hallucinations in Patients with Alzheimer’s Disease During Lockdown
A similar dynamic was documented in people with Charles Bonnet syndrome, a condition where vision loss leads to visual hallucinations. During lockdown, people with this syndrome reported that their hallucinations changed in character: previously small, unobtrusive images grew to life-size and began to move. Some described being followed by shadowed figures or feeling trapped by encroaching plants. Self-reported loneliness tracked closely with these changes, reinforcing the idea that sensory deprivation and social isolation amplify hallucinatory experiences.14BMJ Open Ophthalmology. Exacerbation of visual hallucinations in Charles Bonnet syndrome due to the social implications of COVID-19
Children are not exempt. In one reported case, a previously healthy ten-year-old developed recurrent isolated hallucinations after SARS-CoV-2 infection, with no other neuropsychiatric symptoms. The hallucinations were attributed to the infection itself and responded to corticosteroid treatment.15PubMed. Isolated Hallucination as a Consequence of SARS-CoV-2 Infection in a 10-year-old Child Cases like this are rare, but they serve as a reminder that COVID’s neurological reach extends beyond the elderly and critically ill. When an otherwise healthy child develops unexplained psychiatric symptoms in the context of recent COVID, the infection should be on the list of possible causes.
What Doctors Look For
When a COVID patient presents with hallucinations, clinicians typically work through a checklist to figure out what is driving the symptoms. The evaluation often includes a lumbar puncture to check the cerebrospinal fluid for signs of inflammation or infection in the brain, along with an EEG to look for abnormal brain electrical activity. In one retrospective case series, about 70% of patients who underwent lumbar puncture had normal results, while 30% showed mildly elevated cell counts, protein levels, or pressure.16PubMed Central. Clinical Features and Prognosis of Coronavirus Disease 2019-Related Psychosis: A Retrospective Case Series That means a normal spinal tap does not rule out a COVID-related cause, and the absence of obvious inflammation does not mean the brain is unaffected.
The diagnostic process also involves ruling out other explanations: medication effects (especially corticosteroids and sedatives used in ICU care), metabolic disturbances caused by organ stress, oxygen deprivation, and pre-existing psychiatric conditions that may have been unmasked or worsened by the illness. The timing of symptom onset relative to infection and to any medication changes is one of the most useful clues. Hallucinations that begin within 48 hours of starting a new drug look very different from hallucinations that creep in three weeks after the respiratory illness has cleared.
Treatment Approaches
There is no single treatment for COVID-related hallucinations because the right approach depends on the underlying cause. When corticosteroids are the culprit, reducing or stopping the offending drug usually resolves things quickly, as the case described earlier illustrates. When the hallucinations stem from delirium in an ICU setting, a review of pharmacological approaches found that medications like quetiapine and dexmedetomidine showed benefits in intensive care settings, while evidence for drug treatments in non-ICU settings was weaker. Other antipsychotics such as aripiprazole and risperidone showed potential benefit across different populations experiencing agitation.17PubMed Central. Pharmacological treatment of hyperactive delirium in people with COVID-19: rethinking conventional approaches
For hallucinations suspected to be driven by autoimmune processes, immunotherapy has been tried in some cases, though the evidence remains largely at the case-report level. When the underlying mechanism is neuroinflammation rather than direct viral invasion, anti-inflammatory treatments may help. In the pediatric case mentioned earlier, corticosteroids themselves were the treatment rather than the problem, which underscores how much the correct response depends on identifying the correct cause.
Beyond medications, practical measures matter too. Reducing sensory deprivation appears to help: maintaining social contact, ensuring adequate lighting, keeping familiar objects nearby, and preserving normal sleep-wake cycles can all lower the risk of hallucinations, especially in hospitalized or isolated patients. For people with pre-existing conditions like Alzheimer’s disease or Charles Bonnet syndrome, these environmental interventions may be just as important as any pharmaceutical approach.
When to Seek Help
Phantom smells after COVID are common and usually benign, and most resolve over time without specific treatment. But hallucinations involving voices, visual scenes, or false beliefs warrant prompt medical evaluation. You should contact a clinician if hallucinations are distressing or frightening, if they are accompanied by confusion or disorganized thinking, if they started after beginning a new medication, or if they appeared weeks after COVID seemed to have resolved. A doctor can sort out whether the cause is delirium, a medication side effect, an autoimmune process, or something else entirely, and each of those answers leads to a different treatment path.
For family members and caregivers, awareness is especially important. Patients in ICUs may not be able to report hallucinations themselves. Elderly people with dementia may not distinguish new hallucinations from their baseline experience. Children may not have the vocabulary to describe what they are perceiving. Watching for agitation, apparent responses to things that are not there, sudden sleep disturbances, or uncharacteristic fear can help flag the problem before it escalates.
The Isolation Factor Beyond COVID Itself
One of the more striking findings from the pandemic is how much hallucination risk increased simply because of the social conditions COVID created, separate from the infection. The research on Charles Bonnet syndrome showed hallucinations growing larger, more mobile, and more intrusive during lockdown in people who had never been infected with the virus at all.14BMJ Open Ophthalmology. Exacerbation of visual hallucinations in Charles Bonnet syndrome due to the social implications of COVID-19 The Alzheimer’s findings tell a similar story.13PubMed Central. Hallucinations and Covid-19: Increased Occurrence of Hallucinations in Patients with Alzheimer’s Disease During Lockdown Human brains need a steady diet of social and sensory input. When that diet is cut drastically, vulnerable brains fill in the gaps with fabricated perceptions.
This has implications beyond the pandemic. Anyone recovering from a serious illness in prolonged isolation, whether COVID or something else, faces elevated risk. The finding is a concrete argument for maintaining social connection during illness and recovery, not as a feel-good recommendation but as a genuine intervention against a distressing neurological symptom. If you know someone recovering from COVID alone, regular video calls and visits are doing something measurable for their brain, not just their mood.