Dementia is defined as a decline in intellectual ability to a point that it interferes with social or occupational functioning. Theyre all dementias, but all different.
Family history does mean slightly increased risk.
The most common behavioral changes are increased passivity, irritability and suspicion. Often,the patient has no concerns whatsoever. The key is how their present behavior differs from how they've behaved historically. Its best to have a family member or someone else familiar with the persons history and behavior present to discuss the problem and fill in any blanks. With dementia, very few people ever ask whats wrong with them, and when you do tell them, they dont seem to take it to heart.