It wasn't all that long ago when most people, including many doctors, felt that there really wasn't much point in diagnosing Alzheimer's disease until later stages when symptoms were out of control, so to speak. There are many types of dementia, and so, the thought process went, if you couldn't cure them, what difference did it make what kind it was? Besides, the only way Alzheimer's could be truly determined was by an autopsy.
Well, attitudes have changed. While we aren't likely to see a cure for Alzheimer's disease for years, there has been progress, especially in the area of slowing the progression of the disease. The person who has developed mild symptoms may stay active and productive for a longer time if he or she is diagnosed early and treated with one of the drugs available, such as Donepezil (sold as Aricept), or often a combination of drugs such as Donepezil and Memantine (sold as Namenda).
These drugs, like most, have side effects. Some people find the side effects hard to handle, but often changes in dosage, or just using one of the drugs rather than a combination, will mitigate the side effects and make it possible to stave off the worst of the disease, gaining valuable time for the whole family affected by the disease.
Alzhiemer's is, indeed, a family disease. The person suffering from it views it from the inside, so well described in Richard Taylor's book, Alzheimer's From the Inside Out.
The family watches as the person whom they know and love changes before their eyes. Each stage of Alzheimer's disease takes more of that person from them. Having extra time to be together as a family, enjoy friends, travel and plan for the future is valuable. Every day the worst symptoms of the disease can be delayed is precious. Thus, getting diagnosed early is encouraged by every Alzheimer's group I've ever encountered, as well as most people who have family members with the disease.
The family doctor may be the person to start with, as you should be screened for many different health problems that can imitate dementia. You should have all of your medications checked over by one doctor, even if you see several doctors. I would suggest a double check by your pharmacist. Side effects of medications and/or over medication are often mistaken for dementia, when in reality it's the medications themselves causing the problems.
If your physical health is good, and your doctor just chalks up your concerns as normal aging, it's time to see a specialist. There are various psychiatric disorders that can mimic Alzheimer's disease, so the next step may be to see a psychiatrist. Sometimes getting to see the right doctor is tricky so ideally, at this point, you would find a geriatrician to coordinate your care, unless you are quite young and worried about early on-set Alzheimer's. Then you'd stay with your primary doctor to coordinate care. If your doctor doesn't cooperate, change doctors. The main idea is to rule out other disorders that can mimic dementia.