It takes sharp, active minds and reduces them to voids in which fathers don't know daughters and wives don't know husbands.
It kills victims twice -- once when it erodes all memories and personality and again when victims actually die.
Alzheimer's disease and dementia -- collectively the region's fourth-leading killer -- hit surviving family members particularly hard, causing two or more separate periods of grieving, according to experts and families who have lost loved ones to these brain-degenerative conditions.
Alzheimer's and dementia claimed 3,578 lives in Lake, Porter and LaPorte counties between 1999 and 2010, a Times computer-assisted analysis of U.S. Centers for Disease Control and Prevention data shows.
An official with Indiana's chapter of the National Alzheimer's Association said it's beginning to show up in a younger population and manifesting at a more advanced rate.
There is no known cause or cure, adding to the desperation of people watching loved ones die from the diseases, family members of victims say.
Most people are familiar with the joke, and Marsha Moore, 42, of Portage, hates it.
"When people forget something, you sometimes hear them laugh and say they have Alzheimer's," Moore said. "People crack jokes about it all the time. Nothing makes me more angry."
That's because from the time her stepfather, Raymond Moore, was diagnosed with Alzheimer's in 2003 until his death in 2008, Marsha Moore watched a slow death.
The disease showed itself when Raymond Moore began forgetting little things -- keys or appointments, she said.
Only Raymond's problem wasn't little. In 2005, he dropped his wife Betty off at work in Merrillville and was planning on heading to the bank and gas station, as was his routine, Marsha Moore said.
Only he never made it to the bank and kept on driving. Hours passed and his whereabouts were unknown.
Finally, something clicked in Raymond Moore's head, and he realized he was driving around in Munster. He made his way home, but it would be the last time he would drive. The family took away his keys.
Over the next three years, Raymond Moore's family watched as the once sharp-minded millwright and proud Army veteran lost himself in the disease.
No more puzzles and model-building. Sometimes, he couldn't even piece together where he was, Marsha Moore said.
Once, while watching an episode of "Little House on the Prairie," Laura Ingalls Wilder's character collapsed from heat exhaustion. To Raymond, it all seemed real.
"He ran out into the yard, calling out the character's name and trying to help her," Marsha Moore said.
Eventually, caring for her stepfather became too much for Marsha Moore and her mother. An feeling of guilt set in when they admitted him to a nursing home, where he died in 2008.
"Alzheimer's is no joke," Marsha Moore said. "It's slow death."
A shell of themselves
Lisa Lovell Gauthier, of Highland, isn't laughing, either.
Her mother, Rozanne Lovell, was diagnosed with Alzheimer's at age 50.
"It's one of the worst diseases out there, because the person becomes a shell of who they were," Gauthier, 51, said. "They don't know who they are anymore or the people around them."
The mental and physical decline of Lovell occurred over two decades, from the early 1990s diagnosis to 2010, when she died at age 69.
"I remember one time in the early '90s, dad dropped her off at my house one time, and she went into the bathroom," Gauthier said. "She stared into the mirror and spoke to her own reflection, saying, 'I don't know where I'm at. Can you help me?'"
And in 1994, when her parents were living in Dyer, her father awoke to an empty bed. Lovell had wandered out of the house.
"He found her across the street, barefoot and in pajamas, screaming, 'Help me!'" Gauthier said.
From that point on, she had to be with someone at all times. When Lovell died in January 2010 at 69, there was grief -- but also relief, Gauthier said.
Burdens and grief
The burdens carried by family members of Alzheimer's and dementia patients is greater than most other diseases, said Amanda Janz, of the National Alzheimer's Association's Greater Indiana Chapter.
"They go through two complete grieving cycles with this disease," Janz said. "The first happens while the physical self of their loved one is still here but the mind is not. The second happens after the loved one dies."
Though there is no isolated cause or cure for Alzheimer's or dementia, families of those suffering the effects can take some comfort in entering clinical trials.
"That's where new medicines are tested and treatments tried," Janz said.
Janz said patients also can benefit for a time from medications that appear to slow Alzheimer's progression.
Marsha Moore said her family received comfort, support and information from the Alzheimer's Association.
Janz said her agency offers a 24-hour hotline for caregivers.
A study shows 24/7 caregivers can have their own "lifespans reduced by 10 years or more just from the stress," Janz said.
That's why family members need to keep in check any guilt they feel about relinquishing a loved one to a nursing facility, Marsha Moore said.
"Guilt is a powerful thing when you go through this, but you can't let guilt take over what is rational," she said.