Experts find that postnatal depression is not caused by hormones, contrary to widespread belief. A new study discovers that depression after pregnancy is actually a continuation of current mental problems.

The study led by Professor George Patton from the Murdoch Children's Research Institute investigated a Victorian study that monitored teenagers for 25 years. The research team formed a group of 1,000 participants aged 29-35 and communicated with them every six months. They then listed 384 study subjects with 564 pregnancies. The researchers assessed the women for clinical manifestations signifying depression utilizing the Edinburgh Postnatal Depression Scale. The participants were evaluated three times - at the 32nd week of pregnancy, eighth week after the delivery and one year after birth.

The findings of the study published in the The Lancet reveal that 85 percent of the participants with severe symptoms of postnatal depression suffered from mental health illnesses before pregnancy. Most of these participants have had their mental health problems since they were in their 20s and teenage years. About two-thirds of the women had experienced a form of mental health illness even before the research was initiated 15 years ago. However, the researchers find that women who struggled with their mental health before becoming pregnant did not experience depression during the perinatal stages.

The researchers were also able to come up with a statistical prediction pertaining to depression risks among the study participants. Women who had mental health problems during their teenage years and 20s have a one in three risk. Those who did not have any history of mental health illness have a one in 12 risk.

"For a long time we thought about perinatal depression as being something which is really quite unique," says Patton. "That only occurred at this time in life, and it's something to do with the hormonal disturbances that go with pregnancy."

Perinatal depression encompasses depressive symptoms experienced during and after the pregnancy, thereby impairing nursing practices.

"It has the potential to undermine the maternal infant bond which is so essential to the emotional development of the child," says Patton. "What this really tells us as a study is that we need to think of perinatal depression very much in the life story."

The authors say that the results of the study can help to reduce the incidence of depression during these stages by focusing on high-risk populations, and giving them adequate emotional and social support such as counselling interventions.

Photo: Frank de Kleine | Flickr