I recently got a call from an aging family member who has suffered with bipolar disorder, untreated for most of his life. He explained to me about the police cars that had “surrounded” his home and were “monitoring” him, but really were trying to harm him because they were involved in a “conspiracy with the gangsters who live down the street.”

I sighed. This was just another in a long line of these kinds of episodes, and I was pretty sure it would resolve on its own with my relative hunkering down in his house for a while until he was sure the police had gone away.

But then I decided to go see him as soon as I could, because he just turned 80 and I began to wonder if I should be worried that in addition to his bipolar disorder he might not be showing some signs of dementia. I wasn’t sure about the overlap between bipolar and dementia. We know from studies that people with bipolar disorder often have cognitive problems – memory, executive function, and other thinking problems. But does this put them at higher risk for memory problems in old age?