Why is my parent with dementia seeing things that aren't there?

Published by Unseen Progress, an independent publisher of caregiver research. Last reviewed 2026-07-10. Part of the dementia caregiver research overview.

Short answer. When a person with dementia sees, hears, or believes things that are not real, it is a neurological symptom of the disease affecting how the brain processes perception and reality — not madness, not defiance, and not something they can be argued out of. Hallucinations are false perceptions (seeing a child who isn't there, hearing voices); delusions are false fixed beliefs (that money is being stolen, that a spouse is an impostor). Recurrent, well-formed visual hallucinations appearing early in the illness are a core clinical feature of dementia with Lewy bodies (McKeith et al., 2017). The research-backed response is not to argue reality but to validate the emotion, ensure safety, and rule out treatable triggers — and, for sudden new hallucinations, to consider delirium or a medication cause first (Gitlin, Kales, & Lyketsos, 2012).

Hallucinations versus delusions — and why the difference matters

These two are often lumped together but are different experiences requiring slightly different responses.

  • Hallucinations are false perceptions: the person genuinely sees, hears, feels, or smells something that is not present. Visual hallucinations are the most common in dementia — often people, children, or animals — and are typically vivid and detailed.
  • Delusions are false beliefs held with conviction: that someone is stealing from them, that their house is not their real house, that a familiar person has been replaced by an impostor (Capgras-type), or that a spouse is being unfaithful. Delusions of theft and misidentification are among the most common and the most distressing for families.

Both are symptoms of the brain's perception-and-reality systems being damaged. Neither is under the person's control, and neither responds to being corrected.

The Lewy body clue: early, recurrent visual hallucinations

One pattern is diagnostically important. Recurrent, well-formed, detailed visual hallucinations occurring early in the course of a dementia are a core clinical feature of dementia with Lewy bodies (DLB) in the consensus diagnostic criteria (McKeith et al., 2017). In DLB, alongside fluctuating cognition, REM sleep behaviour disorder, and parkinsonian movement features, vivid visual hallucinations are often present from early on — whereas in typical Alzheimer's disease they tend to appear, if at all, later.

Why this matters practically: people with Lewy body dementia are often dangerously sensitive to antipsychotic medications, which can cause severe, sometimes life-threatening reactions. This is one of the strongest reasons not to reach for antipsychotics reflexively when hallucinations appear, and to make sure the treating clinician knows the full symptom picture. If early visual hallucinations are prominent, it is worth reading Alzheimer's vs other dementias and raising DLB with the doctor.

First: rule out a treatable trigger

New or suddenly worsening hallucinations and delusions are a prompt to look for a reversible cause before assuming disease progression (Gitlin, Kales, & Lyketsos, 2012):

  • Delirium from infection — a urinary tract infection, chest infection, dehydration, or pain commonly triggers new hallucinations or paranoia over hours to days. This is a medical emergency-adjacent situation, covered in delirium vs decline.
  • Medication — many drugs (including some for Parkinson's, bladder, sleep, and pain) can cause or worsen hallucinations. A recent medication change is a red flag.
  • Sensory deficit — poor eyesight and unclear hearing generate misperceptions; a missing hearing aid or dirty glasses can manifest as "seeing/hearing things."
  • Low light and shadows — dim rooms, patterned wallpaper, reflections, and mirrors are common hallucination triggers that are easy to fix.

A sudden change is medical until proven otherwise. A slow emergence over months tracks more with the disease itself.

The research-backed response: validate, don't argue

The strongest, most consistent guidance across the behavioural literature (Gitlin, Kales, & Lyketsos, 2012) is: do not argue about whether it is real. To the person, the perception or belief is real — arguing makes you either wrong or untrustworthy in their experience, and it escalates fear and agitation. Instead:

Respond to the emotion, not the content

The child on the stairs, the intruder in the garden, the stolen purse — the feeling underneath (fear, worry, loss, insecurity) is the real thing to address.

"That sounds frightening. I'm here with you. You're safe."

Meet the fear. You are not confirming the hallucination; you are refusing to fight it and offering the safety the person actually needs.

Don't confirm the false detail, but don't debate it

You need not agree the intruder is real, but you also need not prove they aren't. A gentle redirect after acknowledging the feeling — moving to another room, a walk, a task, a change of light — often lets the episode pass.

For accusatory delusions, don't take it personally or defend

"You stole my money" is one of the hardest, because it is aimed at the caregiver. The research-backed move is not to defend ("I would never!") but to validate the worry and help look: "That's worrying — let's look for it together." Keeping duplicates of frequently "stolen" items (glasses, wallet) can defuse the loop.

Check whether the hallucination is even distressing

Not all hallucinations frighten the person. A benign, pleasant visitor that causes no distress may not need any intervention at all beyond ensuring safety. Intervene for distress and danger, not for the mere presence of the symptom.

What does not work

  • Arguing or "reality orientation" about the hallucination. "There's no one there, look" almost always increases distress and erodes trust.
  • Reaching for antipsychotics as a first move. They carry serious risks in dementia generally and can cause severe reactions in Lewy body dementia specifically; guidelines and the behavioural literature place nonpharmacologic approaches first and reserve medication for danger or severe distress unresponsive to other measures, in clinician partnership (Gitlin, Kales, & Lyketsos, 2012; McKeith et al., 2017).
  • Playing along elaborately. You need not stage the false reality; over-confirming can deepen it. Acknowledge the feeling, redirect the content.
  • Ignoring a sudden onset. New hallucinations overnight are far more likely delirium or medication than steady progression, and that is treatable.

How families ask this

The same neurological symptom surfaces in many forms:

  • "My mom with dementia is seeing people who aren't there — should I be worried?"
  • "He keeps accusing me of stealing his money and it's breaking my heart."
  • "She thinks the people on TV are in the room with us."
  • "He says the man in the mirror is a stranger in the house."
  • "She's convinced I'm not really her daughter."

The accusatory ones cut deepest, because they land on the person doing the caring. It helps to hold onto this: the belief is a symptom of the disease, aimed at whoever is closest — which is you because you are there, not because of anything you did.

References
  • McKeith, I. G., Boeve, B. F., Dickson, D. W., et al. (2017). Diagnosis and management of dementia with Lewy bodies: fourth consensus report of the DLB Consortium. Neurology, 89(1), 88–100.
  • Gitlin, L. N., Kales, H. C., & Lyketsos, C. G. (2012). Nonpharmacologic management of behavioral symptoms in dementia. JAMA, 308(19), 2020–2029.
  • Alzheimer's Association. (2024). 2024 Alzheimer's Disease Facts and Figures. Alzheimer's & Dementia, 20(5).

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Unseen Progress publishes long-form caregiver research. See the full dementia caregiver research overview for the complete framework.