The moms must be crazy

By Anne McIlroy
Saturday, March 27, 2004 - Globe and Mail

Many parents, including Sophia Anglin in Toronto, look back and wonder what came over them in the first few weeks after they had a baby. "She slept so much. I was always staring at her to make sure she was breathing, or sneaking in to listen to her heartbeat," says Ms. Anglin, a bus driver with the Toronto Transit Commission, recalling her first period at home with Vanessa, now six months old.

Other parents report pinching and poking sleeping babies every few minutes to make sure they're still alive, or compulsively scrubbing their children's faces and adjusting their clothes. Friends notice their inability to talk about anything else. It's not their fault. If they seem fixated and obsessive, it's because, clinically, they are. Their brains have been rewired by parenthood.

A Canadian researcher has found the brain activity of new parents is strikingly similar to what is seen in patients who have been diagnosed with obsessive-compulsive disorder. James Swain, at Yale University's Child Study Centre in the United States, says the brain activity he observed in new parents likely led to the kind of behaviour many new mothers reported in the study, including the compulsive need to check on infants.

Dr. Swain and a team of researchers at Yale used functional magnetic resonance imaging to look at the brain activity of 25 couples two to four weeks after they had a baby. They took brain images of the new moms and dads when they heard a tape of their infant crying, or looked at a picture of their newborn.

The data analysis is preliminary, Dr. Swain says. But he and his colleagues found that the brain areas activated were those important for motivation, reward, anxiety and the learning and refinement of habits.

Some of the same circuitry is widely believed to be overactive in the brains of patients with obsessive-compulsive disorder people who can't rid their minds of intrusive worries, Dr. Swain says. They tend to wash their hands repeatedly or worry constantly about being hit by a car or some other disaster.

"It is amazing that some of the same circuits did light up in our parent subjects," says Dr. Swain, who presented his preliminary data at a scientific conference last year. The mothers, however, had a much more pronounced, or intense response than the fathers.

Not that new parents are mentally ill. "No reasonable person would say it is an actual mental illness to be worrying about your baby," Dr. Swain says. Instead, some bits of the brain that have evolved to help us become good parents may be abnormally active in those who suffer from certain kinds of mental illness.

He is one of a growing number of researchers investigating the neurological, hormonal and other physical changes that coincide with becoming a parent. They are finding evidence that parents are biologically primed for their role.

In evolutionary history, parents who fussed over their babies probably had more offspring who grew to adulthood, so those genes were passed on to the next generation. In fact, in obsessive-compulsive disorder, it may be those very networks that are malfunctioning. "Somehow, the wires get crossed in OCD, but maybe our knowledge of OCD can help us understand what parents experience," Dr. Swain says.

Learning about the physiological basis for this kind of behaviour may help prepare people for what to expect when they become parents, says Dr. Swain, who trained as a child psychiatrist in Toronto and Ottawa before moving to the United States to accept a postdoctoral research position. Perhaps it can also be used to help parents who are depressed or otherwise unable to provide the optimal level of fussing, he says.

It makes sense that new parents, and mothers in particular, have special brain mechanisms to help them protect the huge investment they have made in carrying and delivering a baby, says Claire-Dominique Walker, a researcher in McGill University's department of psychiatry. She is investigating a mindset in mothers of newborn infants known as "window-thinking."

The theory based on work in rats is that mothers with young babies aren't stressed out by the same kinds of things that would normally bother them. They are focused so intently that they respond only to stresses that would affect their parenting and the safety of their babies or other children.

Dr. Swain would like to extend his work to grandparents. Many new parents report that grandma and grandpa also become consumed with worry over the new grandchild. "It may be like priming a pump," he says, "which is more easily switched on again when your children have children."