CHICAGO — The baby in Joan Fisher's arms looks perfect: full cheeks, a corona of wispy brown hair and wide, happy eyes through which she seems to take in the whole world.
Gazing at her granddaughter in their home in Darien, Ill., Fisher can see no trace of the legacy that has run through their family for generations. But she knows it could be there, hidden in the girl's DNA, waiting to emerge.
The inheritance is bipolar disorder, a mental illness that afflicts as many as 6 million Americans. It can be tricky to diagnose, hard to treat, devastating to live with.
Much about it remains mysterious, but its genetic nature is clear. The baby's mother has been diagnosed with the disorder and the father might have it, too. That does not guarantee it will show itself in the girl, but it boosts the odds.
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But there are good reasons for hope.
Researchers are getting closer to identifying the genes that cause bipolar disorder. They're using brain imaging to track the illness in a person's neural pathways. And they're zeroing in on triggers that might cause it to flare up. These developments, some experts say, suggest that children born today with a predisposition toward bipolar disorder will have easier lives than their parents. The illness could be detected earlier, managed with more effective medicines, perhaps even prevented with therapy and lifestyle changes.
Medical advances, though, are only part of the equation — and maybe the simplest part.
Advocates for people with mental illness say stigma is rampant despite growing efforts to combat it. They say those who suffer from bipolar disorder are frequently mistreated by police, schools or even relatives, and others are shamed into denial.
"There's still all that negative talk, the way people used to talk about handicapped people or children with Down's syndrome," said Susan Resko of the Child and Adolescent Bipolar Foundation, based in Evanston, Ill. "We're still in that space with psychiatric illness. We don't understand it. It's scary to us as a society."
Hope and fear have been at war for decades in Joan Fisher's family, and she is prepared to face that struggle again with her granddaughter. Although optimistic about the advance of science, she fears that social understanding will lag.
"There are many people with bipolar disorder who live a wonderful life," she said. "I believe that is possible. ... At the same time, I do not believe that society is ready to embrace the idea that for the greater good, we must support those that need support."
Bipolar disorder, also known as manic depression, affects an estimated 2 percent of the population and can be one of the hardest mental illnesses to endure. A severe manic state can cause people to spend money wildly, throw themselves into high-risk sexual encounters or lose their grip on reality. When depression takes over, they can feel exhausted, inert, even suicidal.
Fisher has never been diagnosed with the illness, but its shadow has hung over her. Several older relatives spent time in psychiatric institutions, displayed frighteningly erratic behavior or committed suicide after years of trying to soothe their brains with drugs and alcohol.
But she didn't see the disorder's full power until the early 1980s, when her older sister, Nicole, got sick.
Nicole, then 26 and an architecture student, was diagnosed with manic depression after she became convinced that her parents and the FBI were conspiring against her. During her first breakdown, it took three police officers to get her to a psychiatric hospital.
Nicole went on lithium, a mood stabilizer that remains the most popular treatment for bipolar disorder. But she didn't tolerate it well, leading her doctors to try many other drugs over the years.
They never found the magic formula. Nicole was stable enough to have a successful career as an architect (the boundless energy that comes from mania can do wonders for a person's productivity), but she confessed to Fisher that psychotic thoughts frequently bobbed through her mind.
The hit-or-miss approach to medication produces some of the keenest frustrations for people with mental illness. But some research efforts dedicated to alleviating that are starting to bear fruit.
At the University of Illinois at Chicago's Pediatric Bipolar Research Program, Dr. Mani Pavuluri and her colleagues have used functional MRIs to examine the brain operations of children who have bipolar disorder. They have found that when these kids are exposed to distressing words or images, the part of their brains that regulates emotions is underactive.
The technology is still developing, but Pavuluri said it could help to distinguish people who have bipolar from people with attention deficit hyperactivity disorder.
Scientists also are having some success identifying genes that increase the risk of bipolar disorder. Much work remains — most researchers think the condition stems from still unknown gene combinations — but some say the discoveries promise to make selecting the right medicines, or even creating new ones, much easier.
"You find the genes primarily with the hope of developing novel drugs that we hope will work better," said Dr. William Byerley, a psychiatric geneticist at the University of California San Francisco. "We might be able even to prevent the onset. By knowing the gene, we'll know the neuro biology and know some of the pathways of the disease."
Dr. Kiki Chang, director of the Pediatric Bipolar Disorders Program at Stanford University, said recent research has focused on the idea that treating children early can keep bipolar disorder from emerging in those genetically predisposed toward it.
In one experiment, children who showed mild signs of the disorder were given a drug used to treat mania. It helped with all of their symptoms, suggesting that it might smother the illness before it can bloom.
He said another promising approach is therapy that coaches an entire family to remain calm and supportive.
Fisher said she'll use yoga to try to keep the stress level down around the house, and she'll be keenly attuned to any changes in the girl that might call for early treatment.
Whatever comes, she and her daughter say, they will be ready. And who knows? Maybe they'll be lucky. Maybe this baby, so perfect in Fisher's arms, will never face the illness.
"It's my job to be hopeful," Fisher said.