Delusions and paranoia are among the most distressing symptoms of Lewy body dementia (LBD). A person with LBD might accuse family members of stealing, insist their spouse has been replaced by an imposter, or become convinced that someone is trying to harm them. These aren’t simply moments of confusion. They’re fixed false beliefs that feel completely real to the person experiencing them.
Delusions and paranoia in Lewy body dementia affect up to 70% of people with LBD at some point during the disease. They can strain relationships, create safety concerns, and leave caregivers feeling helpless and hurt. Understanding why these symptoms happen and how to respond can make a significant difference for everyone involved.
Key Takeaways
- Delusions occur in up to 70% of people with LBD and are caused by changes in the brain
- The most common delusion is believing someone is stealing from them
- Capgras syndrome, believing a loved one has been replaced by an imposter, is particularly common in LBD
- Delusions are fixed beliefs that cannot be reasoned away with logic or evidence
- Arguing or trying to prove the delusion wrong usually makes things worse
- Cholinesterase inhibitors may help reduce delusions
- Antipsychotics are risky in LBD and should only be used with extreme caution
- Sudden worsening of delusions may signal an infection or other medical issue
Common Types of Delusions in Lewy Body Dementia
The most common delusion in LBD (as well as in Alzheimer’s) is the belief that someone is stealing. Your loved one may accuse family members, caregivers, or neighbors of taking their belongings. They might hide valuables and then forget where they put them, which reinforces their belief that it was stolen.
Paranoid delusions involve believing others mean harm. Your loved one might think someone is poisoning their food, that people are plotting against them, or that strangers are watching the house. They may become suspicious of people they’ve trusted for years.
Capgras syndrome deserves special attention because it’s particularly common in LBD. People with Capgras believe that someone close to them, usually a spouse or primary caregiver, has been replaced by an identical-looking imposter. They recognize the person’s face but feel something is fundamentally wrong. They might refer to “the real” husband or wife as if the person standing in front of them is a fraud.
Capgras can be devastating for caregivers. The person you’ve cared for, perhaps for years, suddenly treats you with suspicion or hostility. They may refuse your help, become frightened of you, or even become aggressive. It helps to remember that this is the disease, not your loved one’s true feelings about you.
Other delusions in LBD include believing the house isn’t really their home, that dead relatives are still alive, or that events on television are happening in real life.
Why Delusions and Paranoia Happen in Lewy Body Dementia.
Delusions in LBD result from physical changes in the brain caused by the disease. LBD damages areas involved in visual processing, face recognition, and reality testing. When the brain can’t properly interpret what it sees or connect visual information with emotional recognition, it fills in gaps with explanations that feel true to the person.
Delusions often occur alongside visual hallucinations. Cognitive fluctuations, a hallmark of LBD, make delusions unpredictable. Your loved one might recognize you perfectly in the morning and believe you’re an imposter by evening.
How to Respond to Delusions
When your loved one expresses a delusion, your instinct may be to correct them, show them evidence, or explain why their belief doesn’t make sense. This approach almost never works. Delusions are fixed beliefs that resist logic. Arguing typically increases distress and can damage your relationship.
- Don’t argue or try to prove them wrong. Saying “That’s ridiculous” or “I’m not an imposter, look at our wedding photos” won’t change their mind and will likely upset them more.
- Acknowledge their feelings without agreeing with the delusion. You can say “That sounds really scary” or “I can see you’re upset” without confirming that someone is actually stealing from them.
- Offer reassurance and comfort. A calm voice, gentle touch, and reassuring presence can help even when words don’t. Let them know they’re safe and loved.
- Try distraction. Sometimes redirecting attention to a different activity or topic can shift their focus away from the delusion. Suggest looking at photos, listening to music, or having a snack.
- Use sound before sight. With Capgras syndrome specifically, voice recognition often remains intact when face recognition fails. Calling out before entering the room or speaking before your loved one sees you may help them recognize you correctly.
- Consider whether the “imposter” should step away. If you’re the target of a Capgras delusion, having someone else provide care temporarily may reduce distress. Sometimes, leaving the room and returning can “reset” the situation.
- Look for triggers. Delusions may worsen at certain times of day, in certain lighting, or after certain activities. Identifying patterns can help you anticipate and potentially prevent episodes.
When to Seek Medical Help
Contact your loved one’s doctor if delusions are causing significant distress, if your loved one becomes aggressive or a danger to themselves or others, or if there’s a sudden change in the frequency or intensity of symptoms.
Sudden worsening of delusions often signals an underlying medical problem. Urinary tract infections, dehydration, constipation, and pain can all cause delirium that mimics or worsens LBD symptoms. These conditions are treatable, so it’s important to rule them out.
Review all medications with the doctor. Some medications, including those used for Parkinson’s symptoms, can trigger or worsen hallucinations and delusions.
Treatment Options
Cholinesterase inhibitors like donepezil, rivastigmine, and galantamine are often the first treatment tried. These medications can reduce hallucinations and delusions in some people with LBD, particularly in early to moderate stages.
Antipsychotic medications require extreme caution. Approximately 50% of people with LBD have severe, sometimes life-threatening reactions to certain antipsychotics. If one is necessary, only certain “atypical” antipsychotics should be considered at the lowest possible dose. Never allow an antipsychotic to be prescribed without confirming the prescriber knows about the LBD diagnosis. See our article on medications to avoid with Lewy body dementia.
Taking Care of Yourself
Being accused of theft, treated as an imposter, or viewed with suspicion by someone you love can be emotionally exhausting. Caregivers of people with these symptoms report higher burden and more distress than those caring for people without them.
Remember that these accusations aren’t personal. Your loved one isn’t choosing to believe these things. The disease has changed how their brain processes reality.
Seek support from others who understand. Support groups for LBD caregivers can provide validation, practical tips, and emotional relief. Talking with a counselor may also help.
Take breaks when you can. If you’re the target of delusions, stepping away temporarily may be the best thing for both of you.
Our helpline is available every day of the year from 8am to 8pm Eastern time at 516-218-2026 or 833-LBDLINE. You can also reach us by email at norma@lbdny.org.
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Frequently Asked Questions
Why does my loved one think I’m an imposter? This is Capgras syndrome, caused by damage to brain areas that connect face recognition with emotional familiarity. Your loved one sees your face but doesn’t feel the emotional recognition that should accompany it. Their brain explains this disconnect by concluding you must be an imposter.
Should I correct my loved one when they say something that isn’t true? Generally, no. Delusions are fixed beliefs that don’t respond to logic or evidence. Correcting them usually increases distress without changing the belief. Acknowledge their feelings and offer comfort instead.
Can delusions in LBD be cured? There’s no cure, but symptoms can sometimes be reduced with cholinesterase inhibitors and non-drug approaches. Delusions may also fluctuate on their own as part of the disease’s natural course.
Are delusions dangerous? They can be. Someone who believes they’re being threatened may try to defend themselves. Someone who doesn’t recognize their home may try to leave. Safety planning is important when delusions are present.
What’s the difference between a delusion and a hallucination? Hallucinations involve seeing, hearing, or sensing things that aren’t there. Delusions are false beliefs about reality. They often occur together in LBD.
