By CHRISTINE DELL'AMORE Elevated levels of natural copper in a new mother's body may contribute to postpartum depression, a crushing disorder that can occur without warning, researchers report in a new study.Women with a history of postpartum depression had higher blood copper levels compared to those without depression, confirming decades of anecdotal observations, said study co-author William Walsh, director of research at the Pfeiffer Treatment Center in Warrenville, Ill.This may be the missing link in the mystery of postpartum, Walsh said. The medical and science worlds haven't focused on this element, and (now) we have distinctive proof that elevated copper is a feature of postpartum depression.The study, funded by Pfeiffer, appeared in the February issue of the Journal of Trace Elements in Medicine and Biology.Walsh and lead author Dr. John Crayton of Loyola University in Maywood, Ill., studied charts of 14,000 Pfeiffer Treatment Center patients in clinic between 1990 and 2002, and selected 902 charts of women and men ages 30 to 60. The researchers ruled out those with epilepsy, diabetes and other psychiatric conditions. They measured copper and zinc in the blood of 78 women who had suffered from postpartum depression, 148 women with no history of the disease and a control group of 28 non-depressed women. The researchers also compared the results with non-depressed and depressed men.The women who had postpartum depression had copper levels at 131 ± 39 µg/dL, compared with 111 ± 25 µg/dL in the women without such a history.The levels of zinc, which has a reciprocal relationship with copper, did not vary across the groups.Postpartum depression affects about 400,000 U.S. women, leaving them with depressed moods, lack of energy and appetite, sleep disruption and reduced interest in normally enjoyable activities. In severe cases, women may experience suicidal or homicidal thoughts or behavior.This causes great wreckages of their lives, Walsh said. These women were eager to have children, had good marriages -- and then disaster struck after the baby was born.Copper is an essential nutrient present in most foods, in water and in vitamins. During pregnancy, the mother's body produces excess amounts of copper to help the baby grow new blood vessels and capillaries. But in mothers with postpartum, it seems this burst in copper production never subsides, Walsh said. About 15 percent of women experience short-term baby blues, which last only a few weeks; a smaller percentage can suffer from depression for years. Previous research has found elevated copper in the body can spark depression and anxiety, as well as violent behavior. No one knows why copper levels do not return to normal in some women. One of the mysteries is that it persists, said Walsh. He speculates the protein responsible for getting rid of excess copper -- metallothionein -- may be impaired, perhaps due to a genetic weakness. Walsh and colleagues have developed a non-drug, 60-day nutrient therapy that can correct copper levels. The treatment activates metallothionein to rid the body of copper.Women with postpartum depression are often given anti-depressants. Many find relief, but others do not respond to the drugs.However, the researchers have only observed an association, and it's too early to say if elevated copper causes postpartum depression. A controlled, double-blind study is needed to confirm the results.Likewise, the study was limited by its reliance on anecdotal case histories rather than formal diagnoses and evaluations.It's important not to jump to conclusions or to change prenatal or postpartum care with respect to copper, Dr. Nada Stotland, vice president of the American Psychiatry Association, said in an e-mail message. We don't even know whether the elevated copper levels are the cause, the effect, or just an incidental finding in postpartum depression.Stotland, also a clinical psychiatrist in Chicago, said the study was interesting and that perhaps it will be the basis for clinical research over time.More crucial, she said, is that the study reflects the shift toward recognizing postpartum depression as a real disease -- a disease we can effectively diagnose and treat.WASHINGTON, Feb. 22