If dementia is diagnosed following surgery, will it get better once the anesthesia is out of the system? How long does it take for anesthesia to no longer cause problems in the elderly? Is it possible for anesthesia to remain in the system for a year or two? Surgeon said his reaction to anesthesia was more pronounced because he has underlying dementia. I've been told by a few people that my husband's dementia or dementia like systems could disappear a year or two after sugery, since it's possible for anesthesia to remain in the system for a year or two. I've been told so many things by so many people I don't know what to believe anymore. My husband does appear fairly normal at times, but anyone who works with him in assisted living say that he displays signs of sundowner syndrome in the evening. He is determined that one way or the other, he is not going to be staying in A.L., he now wants to see a psychiatrist to prove there is nothing wrong with him, even though A.L. staff, family doctor, therapists, etc. insist he needs A.L. Many times he has informed me that a friend is picking him up and taking him to a ball game or that he has been asked to be in involved in a charity auction at a service organizaiton and needs a ride. When I call to confirm it, I am told that simply is not true. I'm not comfortable thinking of him coming home, since he can not be trusted; told me if he came home, he would buy another car and drive it, spend money just like he used to, live his life just as he did prior to all of this. (his driving is extremely dangerous).