9 Brain Disorders That Completely Warp Your Reality

7. Phantom Boarder Symptom: There's Someone In My House

It sounds utterly terrifying, but some people with dementia will also suffer from the delusion that there is somebody, usually unwelcome, living in their house.

Those with phantom boarder symptom will often have incredibly detailed ideas as to the behaviour of their phantom houseguest, sometimes complaining that they are noisy, or even that they keep eating the patient's food. It's like having the housemate from hell, but one that doesn't respond to passive aggressive notes.

The delusion is thought to be a problem with misidentification, and that the patients are incorrectly attributing memories of events and the behaviour of others (in the case of the noise) or even themselves (in the case of the missing food) to their non-existent housemate.