Compared with Alzheimer's disease, which causes 50% to 60% of dementia cases, brain tumors account for an estimated 3% of cognitive deterioration.

Compared with Alzheimer's disease, which causes 50% to 60% of dementia cases, nutritional-deficiency dementia accounts for an estimated 5% of cognitive deterioration. The nutrient deficiencies most closely associated with dementia are the B vitamins: thiamin (B-1), niacin (B-3), folate (folic acid), and vitamin B-12. Of these, folate and B-12 deficiencies are most common.

Compared with Alzheimer's disease, which causes 50% to 60% of dementia cases, drug-related dementia accounts for an estimated 5% of cognitive deterioration. Many medications taken by older people can cause subtle cognitive impairment. But when older people take several drugs simultaneously -- as many do -- significant cognitive problems may emerge that mimic Alzheimer's disease: memory loss, absent-mindedness, confusion, disorientation, and emotional outbursts.

Compared with Alzheimer's disease, which causes 50% to 60% of dementia cases, Pick's disease accounts for about 5% of cognitive deterioration. Pick's disease was first identified in 1892 by Dr. Arnold Pick, who described progressive mental deterioration in a 71-year-old man. On autopsy, his brain showed unusual shrinkage of the frontal cortex, the region involved in reasoning and other higher mental functions.

Compared with Alzheimer's disease, which causes 50% to 60% of dementia cases, alcoholic dementia accounts for an estimated 10% of cognitive deterioration. The typical person with alcoholic dementia has a long history of alcohol abuse. However, stereotypes of alcoholics are often mistaken. Many alcoholics function reasonably well for many years and drink in secret, so their friends and loved ones may be unaware of the extent of their drinking.

Compared with Alzheimer's disease, which causes 50% to 60% of dementia, experts estimate that multi-infarct dementia (MID) accounts for about 15% of cognitive deterioration, making it the nation's second leading cause of dementia.

Alzheimer's disease is the nation's leading mind-robber -- but it's not the only one. Many other conditions can cause symptoms that might be mistaken for Alzheimer's. Some rare dementing conditions, such as Pick's disease, are less treatable than Alzheimer's and fatal within about a decade. But most non-Alzheimer's conditions that cause dementia are fairly treatable.