I don't think my 78-year-old mother has dementia, so why does she get sundown syndrome?

While your mother could be suffering from an early form of dementia, she may -- like a lot of elderly people -- get disoriented for some other reason associated with that time of day. Either way, there are some practical things you can do.

Make sure your mother isn't alone in her room during the evening. The assisted living facility may already offer organized activities for people like your mother to keep them occupied and distracted. Some research suggests that sundown syndrome is a light-related phenomenon, so it may help to have your mother spend more time in a well-lighted room.

That said, it's important to recognize that these behaviors could be the first signs of dementia. Whether or not you want to have your mother evaluated is another question, because once someone is labeled as having dementia, she's going to be treated differently by the assisted living facility.

In addition, there's no effective treatment for dementia. There are experts who would argue that the medications prescribed to maintain cognitive and functional ability in people with dementia have shown some benefit, but my understanding is that the results are very mixed.

Your mother's anxiety about someone stealing from her doesn't sound like a worry that would only strike at sundown. Keep in mind that older people can get paranoid at any time of day; they may just get more agitated about it in the evening.

For example, older people can become anxious and suspicious when they're hard of hearing. Any major sensory deprivation, such as vision or hearing impairment, can contribute to a feeling of paranoia, but in reality, older people rarely develop true psychosis.

If your mother is showing paranoia, something else is probably going on. It could be metabolic, sensory, or the beginning of dementia -- all good reasons to evaluate what's going on rather than ignore it, so you can find out whether the condition can be treated.