She's Suspicious of Everyone, Not Just About Theft

A brain that cannot retrieve where the purse was set down will still produce an explanation, and the explanations available are the ones that fit the evidence in the room. The purse is gone. Someone was here. Someone took it. That is a gap being filled rather than a judgment being formed, which is why arguing the facts so rarely works. Delusions are common, affecting something like a third of people with Alzheimer's at some point, though the studies range widely enough that no single number is worth trusting.

The specific forms are far less frightening once they have names.

• Capgras. Capgras is the belief that a spouse or adult child has been replaced by an impostor, reported in around one in six people with Alzheimer's and more often in Lewy body dementia.
• Phantom boarder. Phantom boarder is the belief that someone unseen is living in the house.
• Mirror sign. Mirror sign is not recognizing her own reflection.
• Television. Television can stop being a representation and become an event happening in the room.
• Infidelity. Accusations of infidelity are usually about fear of abandonment rather than about sex.

Capgras deserves its own line, since it targets the person emotionally closest, which is why it lands on you, and published case reports have repeatedly linked it to aggression toward the person who is not recognized. That makes it a safety matter. If there is a gun in the house, this is the paragraph to act on: someone who does not recognize you and believes an intruder is in her home may act on that belief, and the Alzheimer's Association's guidance is to move firearms out of the house rather than into a safe. The same logic applies to car keys and, if she has ever reached for one, kitchen knives.

One distinction changes what happens next. A delusion is a belief that will not shift. A hallucination is seeing or hearing something that is not there. If she is seeing people, children or animals in detail, and particularly if that began early in the illness, that points toward Lewy body dementia, and the clinician needs to hear it in plain words because it changes which medications are safe.

Then check the ordinary things. Pain drives more distressed behavior than anything else you can fix. Uncorrected hearing and vision loss feed suspicion directly, since a person who hears voices in the next room but not the words will supply the words. Medications belong on the list too, particularly bladder drugs and sedating antihistamines, opioids, steroids, Parkinson's medications, and anything recently stopped, including alcohol.

And one uncomfortable thing has to be said. When the accusation names a specific paid caregiver, check before you dismiss it. Do not leave her alone with that person while you do. Look for unexplained bruising, money that does not add up, and distress that appears only around one person. Nearly all of these accusations are the illness. Not all of them are, and Adult Protective Services through the Eldercare Locator, 1-800-677-1116, is where it goes if you find something.

The delusion says you are an impostor. It does not say she has stopped knowing you. What has most likely failed is the part of the brain that attaches the feeling of familiarity to a face, so your face is right and the feeling that should come with it is missing. Many families take it as a sign of how central you are that it landed on you rather than on a stranger. Nobody can promise what she feels underneath, and you do not need that promise to keep going. For most families this eases over months rather than continuing forever, which is worth holding onto.

Look for the cause before you reach for the technique, since most of what drives this is findable.

1. Check pain, then hearing and vision. A person who cannot hear the room will fill in the gaps, and the fill is rarely generous. Working hearing aids and clean glasses are an intervention here rather than an accessory.
2. Reduce what there is to misread. Close the curtains after dark so the window stops producing a stranger, keep news and crime drama off, and put a lamp on in the corner she watches. Cover a mirror only if her own reflection distresses her.
3. Keep duplicates of whatever goes missing. Two purses, two sets of reading glasses, a little cash somewhere she can find it. This ends more accusations than any explanation.
4. Take the full medication list to the pharmacist, including anything stopped in the last few weeks, and ask whether any of it could be feeding the suspicion. Bladder pills, some allergy and sleep medicines, strong painkillers and steroids are common culprits, and a change caused by a medicine can usually be undone. Do not stop anything yourself. Ask first.

Write down when it happens, what was going on twenty minutes before, and who it names. If it clusters late in the day, the fix belongs earlier in the afternoon. If it names one particular person every time, check rather than dismiss. And if the pattern changed shape over days rather than months, that belongs on the phone rather than in a notebook.

Print the one-page log if you want somewhere to keep this, and take it to the appointment.

This is what the tracking is for. Dates, times and specifics turn "something's off" into something a clinician can act on in a ten-minute appointment.