Katie Forbish never dreamed she'd be helping her mother-in-law go to the bathroom. She definitely never imagined herself scouring cat feces from Lynn Forbish's basement crawl space -- when Lynn could no longer change the litter box.

As hard as being a caregiver is sometimes, Katie can only imagine how difficult it must be for spouses of dementia patients. More than 40 percent of caregivers suffer from clinical depression, according to the national Alzheimer's Association.

"Many caregivers wear out long before the patient does," said Annette Clark, regional director of the Roanoke Area Alzheimer's Association. One-third of caregivers die before the person they're caring for does.

The Roanoke region reports 20,500 cases of dementia, most of them Alzheimer's patients, Clark said. Experts predict the prevalence of Alzheimer's and related dementias will soar to 7.7 million nationwide by 2030. By midcentury, the number is projected to grow to 16 million, more than the populations of New York City, Chicago, Houston and Los Angeles combined.

"We're at the tip of the iceberg," said geriatrician Dr. Michael Berry of the Carilion Center for Healthy Aging. Berry believes the current numbers are underreported, with costs threatening to one day put a chokehold on Medicare and Medicaid.

Unpaid caregivers of people with dementia provide 8.5 billion hours of care annually valued at almost $83 billion. The vast majority of people with dementia -- 70 percent -- live at home, cared for by family and friends, and one-third of the caregiving population is older than 60.

Isolation is as common for caregivers as it is among patients.

"I hear caregivers saying all the time, 'We played cards almost every Friday night with friends for years, and now they won't come see us anymore,' " Clark said.

"People don't know how to respond so they don't respond at all. They're embarrassed -- especially if the person is having difficulty with communication or toileting."

Katie and Larry Forbish have experienced a similar reaction among their peers. "A lot of our friends just don't get it," Katie said. Last summer, she and Larry cut a long-planned vacation to Germany in half because Lynn gets distraught if they're not in daily contact.

"I got off the plane in Germany, and my best friend said, 'Oh my god, you've gotten so old.' The night before we had to fly back, I cried and cried" about the responsibilities awaiting her.

Most nights she comes home from her high school teaching job, helps her daughter with after-school activities and homework, makes dinner -- and then talks to Lynn for an hour on the phone. They spend Sundays with Lynn, and Larry visits at least once during the week.

Friends question their need to be so involved in Lynn's care.

"I see where they're coming from, but it's a choice we've made. Would she be doing this for me? Hell no. But that doesn't matter. This is what my brain and heart and our family has decided is the right thing to do."

The Roanoke Area Alzheimer's Association offers referrals for dementia patients and caregivers, support groups, educational programming and "respite grants" for full-time caregivers in need of a break. Call 345-7600.