When Kimble and Shellie Elmore of Los Angeles adopted Tania, a 10-year-old Russian girl, they thought they were getting an “angel.” Within days, however, they soon learned their new daughter had a violent past. After she tried to stab her father, doctors diagnosed her with bipolar disorder, post-traumatic stress disorder, and attachment disorder. “We know she’s just a child and we want what’s best for her,” says Kimble. “But we don’t know how to help her. Adoption is supposed to be a touchy-feely thing surrounded with the glow of new parenthood. But no one says, ‘What if the worst happens?’”

While the Elmores’ story is rare amidst a sea of adoption success stories, they are not alone in their struggles:

Why do some adoptions go so wrong? Clearly, it’s not the kids’ fault. Their behavior is usually the result of trauma, mistreatment, malnutrition or institutionalization in their home countries—problems more common in places like Eastern Europe. But “the country of origin doesn’t matter so much as the child’s experience,” says Dr. Dana Johnson, director of the University of Minnesota’s International Adoption Clinic. Some are found to suffer from fetal alcohol syndrome, mental illness or reactive attachment disorder, an inability to bond with a parent. Prospective families undergo an arduous screening process, including home visits, and specify how much disability they can handle. But even families who specifically request a “healthy” child sometimes go home with a troubled one. In some cases, the mismatch is inadvertent. But in others, orphanages or adoption agencies overseas—eager to find homes for difficult children in their care—mislead prospective parents or fail to disclose the full extent of a child’s problems or personal history.

Psychologist Karyn Purvis has conducted extensive research of troubled adopted children and believes some of the problems could be mitigated if the adopting parents received more training before and after the adoption. “Very few agencies are training parents to deal with brain damage, sensory deprivation, aggression,” Purvis said. “A lot of these parents are smitten with the hope that they’ll make a difference in a child’s life, but they need very practical tools. I consider myself very pro-adoption. But I’m also very pro informed adoption.”