They're patients who try doctors' patience, making appointmentafter appointment, seeking relief from symptoms with no apparent cause. Though many physicians dread encountering these "difficult patients," University of Washington psychiatrist Edward Walker, M.D., sought them out--to study the reasons behind their behavior. Such patients have several things in common, he found: they report frequent, ambiguous aches and pains, feel a lack of control over their illness, and tend toward the obsessive compulsive. Noting that many were unmarried, Walker speculates that they are turning to health care providers for social support. Yet they are often wary and suspicious of their doctors--with good reason, he says, given that many were abused as I children and have likely learned to distrust authority figures. Doctors, in turn, may feel unable to help such patients, and so avoid them. A psychiatric evaluation of the patient might break this pattern of approach and avoidance, says Walker. It might also point out new directions for treatment. And simply knowing that some personality problems are not under patients' control, he says, may help physicians be more compassionate.