For Max Stevenson,* another missed mortgage payment was almost the last straw. His wife, Elizabeth,* intended to pay the bill but hadn't followed through—yet again. "I had two children with Elizabeth, but I also had Elizabeth in the role of a third child," he says. "Not only was I trying to organize my own busy personal, professional and domestic life, but I was also trying to steer her. I felt alone and also really desperate."

Max is quick to add that Elizabeth is incredibly creative and wonderful in many ways. But for years, her untreated attention-deficit hyperactivity disorder (ADHD) threatened to pull them apart.

Their story is not unusual. Troubled relationships are all too common among adults with unmanaged ADHD, says Kevin R. Murphy, PhD, president of the Adult ADHD Clinic of Central Massachusetts and associate research professor in the department of psychiatry at SUNY Upstate Medical University in Syracuse.

"In fact, it would be rare that ADHD wouldn't affect the marriage," he says.

The good news, though, is that adult ADHD is highly treatable, says Ned Hallowell, MD, a psychiatrist who specializes in treating ADHD at the Hallowell Centers in New York and Boston, and coauthor of "Driven to Distraction," a best-selling book on adult ADHD. "The right diagnosis can turn marriages and lives around," he says.

Most of the research on ADHD is focused on children. According to the Centers for Disease Control and Prevention, 9.5 percent of kids age 4 to 17 have been diagnosed with the disorder. Some of those children seem to outgrow it, but for others symptoms persist into adulthood. In a 2006 study, Russell Barkley, PhD, a clinical neuropsychologist at the Medical University of South Carolina in Charleston, and colleagues determined that about 4.4 percent of the adult population suffers from ADHD (American Journal of Psychiatry, Vol. 163, No. 4).

Although the disorder afflicts millions of adults, it remains badly underdiagnosed, Barkley says. His study also found that only about 10 percent of adults who met the diagnostic criteria for ADHD had been diagnosed and treated for it.

Partly, that's due to misconceptions about the disease. "For decades it was thought to be just a childhood disorder, and everyone thought it declined markedly by adolescence," he says. "For many decades, many mental health professionals received no training in this disorder, particularly if they were specializing in adults." That finally started to change in the mid- to late 1990s, he says, and awareness of and education about adult ADHD continue to improve.

It's true that the hyperactivity component of ADHD often declines with age. But other, equally insidious symptoms can linger into adulthood. Classic signs include difficulty with focusing, organizing, planning and follow-through.

"It feels like there's a carnival in my head," Elizabeth Stevenson says. "My brain is going in so many different directions, it's very difficult to look at a list and pick out what I need to do first."

ADHD is a neurobiological disorder. Symptoms are thought to stem from underactivity in the frontal cortex—the brain's control panel for attention, self-control and executive functioning. People with ADHD typically show a decrease in blood flow, glucose metabolism, and levels of the neurotransmitters dopamine and norepinephrine in that part of the brain, Murphy says.

Despite the name, the syndrome is far more than a deficit of attention. "Research shows it's a disorder of executive functioning," Barkley says. Executive functioning involves five areas of daily behaviors, he explains: time management, organization, motivation, concentration and self-discipline. He and Murphy recently reported in the Journal of Psychopathology and Behavioral Assessment that 89 percent to 98 percent of adults with ADHD are impaired in all five areas.

"There's no domain of your life that this disorder does not interfere with. It produces more significant impairment in more areas of life than other outpatient disorders," including anxiety and depression, Barkley says. "School, occupation, money, credit, sex, work life, raising children—it hits them all."

Marriage teeters

As the Stevensons learned, undiagnosed ADHD can hit relationships hard. Research findings on the relationship between divorce rates and ADHD are somewhat mixed, but several studies have turned up a link. In a paper in Comprehensive Psychology, Barkley and Murphy reported that patients with ADHD had a higher mean number of marriages, and that they and their spouses reported lower levels of marital satisfaction, than did people without ADHD. Together with co-author Mariellen Fischer, PhD, Barkley and Murphy also touch on the problem in their 2007 book "ADHD in Adults: What the Science Says."

In relationships in which one partner has undiagnosed ADHD, a parent-child dynamic usually develops, says Melissa Orlov, a marriage consultant specializing in ADHD and author of the 2010 book "The ADHD Effect on Marriage."

"The non-ADHD partner becomes responsible for everything, and the ADHD partner starts to feel like a child in the relationship," she says. "It's very unromantic."

Other familiar patterns play out time and again. Individuals with ADHD often have a pattern of chronic underachievement that can lead to insecurity and depression, says Hallowell. "They feel shame and frustration. Without the diagnosis, they can't make use of their talent," he says. "The marriage teeters because of that."

And because individuals with ADHD are easily distracted, they often forget to do household chores as promised, and may seem to be ignoring their spouses or children. "The non-ADHD partner interprets that as being lazy and not caring about the family," says Orlov. Anger and resentment build, though the non-ADHD partner often has no idea what they're doing wrong. "The symptoms are stomping around in the marriage, and they just don't know it," she says.

Unfortunately, traditional marriage counseling often isn't very helpful unless ADHD is diagnosed and treated. "Many people have tried going to therapists and marriage counselors who are not trained in ADHD and may overlook it as a source of potential problems in the marriage," Murphy says. "Consequently, these well-meaning therapists may miss the boat, which is a major reason why many ADHD couples report prior attempts at traditional couples counseling to be unhelpful."

That was certainly the case for the Stevensons. About 11 years ago, their son was diagnosed with ADHD—and a light bulb went on when Elizabeth recognized the symptoms in her own behavior. She was diagnosed soon after, but for years she struggled to find someone who could help. "We sought out professional marriage therapists, individual therapists. At no time was anybody ever bringing up the ADHD," Elizabeth says. "With that one piece missing, it was like the 800-pound gorilla in the room."

The first step to tackling that gorilla is to get a proper diagnosis. Then, it's crucial to rediscover empathy for one another, Orlov says. After years of undiagnosed ADHD, layers of resentment have often built up. To peel back those layers, couples need to regain some compassion for one another. "It doesn't mean you're still not madder than a wet hen, but you have a reason to overcome it," she says.

Usually, she adds, the person with ADHD really wants to do better. "They don't like being at the receiving end of a frustrated spouse. They've been trying, but because they haven't known about ADHD, they haven't known how to fix it," she says. "Trying harder doesn't work. You have to try differently."

A medical diagnosis

Educating patients about ADHD is crucial, says Hallowell. Frequently, people with the disorder feel inadequate and suffer from low self-esteem after years of not living up to their potential. Through therapy, affected individuals can overcome the shame and embarrassment of their symptoms and come to recognize their personal strengths, he says. "The patient needs to own the diagnosis to get the best result."

Psychologists have begun to fine-tune their approach to the disorder, Barkley adds, and a number of research groups have recently designed training programs for ADHD. "There are new cognitive behavioral programs developed specifically for adults with ADHD, focusing on executive functioning," he says.

Spouses also benefit from education and therapy. It's important for both partners to believe that ADHD "is a medical diagnosis, not a moral diagnosis," Hallowell says, so that they can they move past blame and toward improving the relationship. "All that is critical, and often clinicians don't take the time to do that."

Once ADHD has been identified and is being managed directly, couples can begin to do the work of rebuilding their relationship together. "It's very important that the non-ADHD spouse doesn't adopt the attitude of pointing the finger at the person with ADHD and saying this is your problem," says Murphy. "There needs to be a shared responsibility and an understanding that this is a family issue, not just the patient's issue."

Most patients see significant benefits from drug therapy as well. Drugs are effective in 70 percent to 80 percent of adult ADHD patients (Journal of Clinical Psychiatry), and often lead to significant improvements. "When medication works, it's as dramatic and as effective as eyeglasses," Hallowell says.

Elizabeth Stevenson began taking medication about a year ago, she says, and she and Max both noticed substantial improvement right away. "On medication, I can function in a more organized, linear way. It's like the swirling in my brain stops," she says.

The Stevensons have been working with Orlov for the last year. Though they consider themselves a work in progress, they say their relationship has gotten much stronger after finally finding someone to treat the underlying issues surrounding Elizabeth's ADHD. "We got lucky," Max says.

With a tailored combination of drug treatment and counseling, most people with ADHD can overcome the condition. "By every metric, this disorder is more treatable than anxiety, depression or other outpatient disorders. The problem isn't that we don't have good treatments, it's that most people don't know they have the disorder," Barkley says. "It is the most treatable disorder in psychiatry, bar none."

Hallowell urges mental health professionals to learn more about the condition so that affected individuals can get the help they need to put their lives on track. To that end, he, Murphy and Orlov have developed a continuing-education seminar for counselors called "The ADHD Effect on Couples."

Barkley agrees that mental health specialists need to better understand adult ADHD. "It's a valid disorder that arises from neurological and genetic factors," he stresses. And because it's highly treatable, he adds, it's an incredibly satisfying specialty. "If you want to specialize in any disorder, pick this one," he says. "It will be one of the most rewarding careers you can have."

Kirsten Weir is a writer in Minneapolis.

*Names have been changed