Psychosomatic illnesses shouldn’t be confused with imagined conditions. Helping those who imagine or feign illness is different from — and harder than — treating psychosomatic illness, says Dr. Marc Feldman, a nationally known expert in psychosomatic medicine.

“We’re probably more advanced right now in understanding the brain-body connection. But when you talk about the mind and the role of fantasy, we’re a long way off,” he says.

Hypochondria is a particularly vexing problem. Studies show that about 9 percent of people who seek care at general medical offices are “card-carrying” hypochondriacs, Feldman says. These people complain of pain, fatigue and other vague symptoms, but doctors are unable to find a reason for their complaints. Unexplained medical conditions account for about $20 billion in health-care costs each year in the United States, Feldman says.

“Hypochondriasis is the faulty conviction of having a serious disease, despite evidence to the contrary,” he says. “These people are not psychotic. They are just illness-obsessed.”

Because the patient believes he or she is sick, it’s sometimes difficult for doctors to distinguish between a real and an imagined illness. Even when every biological cause is ruled out, patients often reject the idea that they are imagining their ailments.

“It’s enormously hard to treat hypochondriasis. That has to do with the fact that these patients aren’t deliberately deceiving the doctor. They believe what they’re saying,” Feldman says.

No one understands what causes people to believe they are sick, but research suggests hypochondriacs are more sensitive to normal body sensations and are more preoccupied with their health.

People with so-called factitious disorders, however, are fakers. These include malingerers, who make up an illness for some gain (such as to collect disability payments), and people with a psychiatric disorder called Munchausen’s syndrome, in which people make themselves or a loved one ill (such as by poisoning) to get attention. Treatment of Munchausen’s requires intense psychiatric therapy.

Hypochondriacs, meanwhile, can sometimes be successfully treated with mental health therapy and regular, short visits to the doctor, Feldman says. The therapy can help patients explore how they think about illness, uncovering faulty ideas, such as, “if my head aches I must have a brain tumor.”

Regular visits to the doctor are a way to assure the patient that, if there is a physical problem, it will be discovered.

Feldman says he has also learned to embrace “innocuous” alternative therapies, such as some herbs or acupuncture, because people sometimes feel better if they believe a treatment is working — a basic tenet of all mind-body medicine. Says Feldman, “The placebo effect can be very powerful.”