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If someone close to you has Alzheimer's disease, how sure are you of the diagnosis? Surprisingly often, I come across caregivers who aren't certain. Often the person refuses to see a doctor. Or one relative has declared it Alzheimer's and now everybody else has just gone along. Sometimes nobody wants to call it anything: It's Grandma's problem. Or the umbrella "dementia."

(Dementia, btw, is a great term; it describes a group of symptoms, including memory loss, slowed thinking, and confusion. But it's not itself a disease or a diagnosis. Alzheimer's is a disease; dementia is how it plays out in the person. Of the many possible causes of dementia, Alzheimer's is only one –- albeit the most common.)

Faced with certain symptoms that indicate mental confusion in a relative of a certain age, most of us automatically assume Alzheimer's. That's the up side of the aggressive awareness campaign about Alzheimer's disease: We're all definitely aware.

Lost in the long shadow of Alzheimer's, though, are a bunch of not-uncommon-yet-little-known Alzheimer's masqueraders, conditions that can create symptoms like those of Alzheimer's but may warrant different treatments.

Earlier this week, New York Times health columnist Jane Brody highlighted one of these. And unlike AD, it's reversible. So I'm putting it at the top of the following list of health conditions that seem like Alzheimer's... but aren't Alzheimer's:

1. Normal pressure hydrocephalus (NPH)

NPH is a build-up of spinal fluid in the brain that causes pressure on nerves. As many as 10 to 15 percent of people with dementia may have it. Don't miss Brody's account of how a 74-year-old man had a reversal of fortune, with the right diagnosis. (Thanks to an alert daughter, by the way.)

2. Frontotemporal dementia (FTD)

FTD is the progressive deterioration of the frontal lobes of the brain. Pick's disease is one form. While FTD appears similar to AD, there are more problems with changes in personality, morals, social conduct, compulsive behaviors, and language (finding the right word, saying inappropriate things).

3. Depression

Depression is caused by chemical imbalances in the brain; especially in older adults, the results can look like the cognitive problems of Alzheimer's. Learn more about how depression and dementia differ.

4. Delirium

I wrote about delirium not long ago, and it's worth knowing about. Watch for it after hospitalizations and stressful procedures, especially. It doesn't only affect people with dementia.

5. Bad drug interactions.

Another thing to suspect if the memory problems and confusion seem sudden are new medications being taken. Older people tend to take multiple meds; the more they take, the greater the risk for problematic interactions.

6. Alcoholism

Memory loss and confusion are a common byproduct of chronically abused alcohol and drugs. Long-term use damages the brain right along with the liver, heart, etc. So if your older relative drinks a lot, for example, what seems like Alzheimer's disease may have an entirely different origin.

7. Dementia with Lewy Bodies (DLB)

DLB is a combination of dementia and Parkinson's disease. A tremor, shaking movements, a distinctive stooped shuffle, and a loss of facial expression join the Alzheimer's-like symptoms of memory loss and slowed thinking. Knowing the difference is useful because different caregiving tips may apply.

Interestingly, I don't have an exact diagnosis in my own dad's case, though I know he has none of the above. That's because his doctor (like many doctors) feels that his dementia symptoms are being caused by either Alzheimer's disease or vascular dementia, which is chronic impaired blood flow to the brain -- or both. The two diseases are very difficult to tell apart, and many people have both.(Some new research indicates they probably have a lot of roots in common.) Moreover, there's no real treatment for vascular dementia, aside from managing cerebrovascular health. (Dad does show evidence of prior small strokes.) So he takes Alzheimer's drugs, and we follow the caregiving advice about Alzheimer's, which is relevant and invaluable.

But of course we did have him checked out in the first place. Diagnosing "pseudo-Alzheimer's" disorders is often a matter of ruling things out. That's why a comprehensive workup at a memory clinic or by a physician who treats a lot of older patients is always recommended.

And who wouldn't want to be like the daughter Jane Brody wrote about, who was nagged enough by her dad's symptoms to press for more evaluation, and then, with the right treatment, got his old self back? It's rare, but it's nice to know it happens.