Research Notes

What behaviors contribute to crib death?

The apparent success of a public health campaign encouraging parents to put infants to sleep on their backs offers reason for further study of behavioral factors that may lead to crib death, according to the founding director of Brown's Child Study Center.

Lewis Lipsitt, professor emeritus of psychology, medical science and human development, argued in the October issue of Current Directions in Psychological Science that research should examine the developmental stages in the early months of life in an effort to answer unresolved questions about what exactly causes Sudden Infant Death Syndrome (SIDS).

"I'm looking for a greater awareness of the behavioral factors that contribute to SIDS," said Lipsitt. "We, our society, and even scientists, tend to have blinders on to behavioral factors."

In developed countries, SIDS remains the leading cause of death for children younger than of 1 yet the causes of SIDS are still a mystery, said Lipsitt. Most deaths occur at 2 to 5 months of age.

Infant development within that three-month window may hold a psychobiological explanation for vulnerability to SIDS, according to Lipsitt.

SIDS research should now look at whether the strong reflexive behaviors that protect the infant from suffocation during the first months of life sometimes wane too quickly, and before learned behavior is sufficient, leaving an infant in jeopardy of SIDS.

Babies are born with a respiratory defense response that causes the baby to react to anything covering its nostrils and mouth - a reflex that can be assessed during the first few days of life. However, studies have shown that after the first two months of life, those reflexive behaviors are gradually replaced by learned deliberate responses, according to Lipsitt.

"If the transition from predominantly reflexive to learned behavior does not take place seamlessly," according to Lipsitt, "the child of two to five months will be at greater risk for SIDS."

"An enhanced program of governmentally sponsored research on the reflexive behavior of infants in the early months of life should be mounted," he wrote. - Kristen Cole

Depression and smoking cessation

Results of a new study counter the common conviction that a history of depression reduces one's chances for quitting smoking

The study found that experiencing a "depressive episode" during one's lifetime does not necessarily predict failure in smoking cessation treatment.

The findings offer hope to smokers who may have been discouraged from trying to quit smoking in the past because of their depression, or who may have been unsuccessful due to mismatched treatments, said the study authors.

"We hope these results encourage clinicians to take a fresh look at how they treat smokers who have experienced depression at some point in their lives," said study leader Brian Hitsman, research fellow in psychiatry and human behavior.

"Clinicians should base their treatment recommendations on the same smoker characteristics, such as level of motivation to quit or degree of nicotine dependence, which are used to determine treatment for smokers in the general population," he said.

Hitsman led a team of researchers whose findings appear in the August issue of the Journal of Consulting and Clinical Psychology. The investigators analyzed results from 15 previous studies that examined the relationship between history of depression and ability to quit smoking in treatment, involving a total of 2,984 smokers. They found that smokers with a history of depression were just as likely to quit smoking than those without such a history.

Smokers have higher rates of depression than nonsmokers. About 17 percent of the U.S. population has a lifetime history of major depression. Up to 60 percent of individuals in smoking treatment programs have a history of depression. The national smoking rate is about 23 percent. Up to 75 percent of people in treatment for major depression are daily smokers.

"It is unclear whether other forms of depression, such as recurrent major depression, interfere with quitting," said Hitsman. "We suspect that specific subgroups of smokers, including those who have had multiple episodes of depression, may require specialized, intensive smoking cessation treatment."

The National Institute on Drug Abuse, National Heart, Lung and Blood Institute, and National Cancer Institute supported the study. - Scott J. Turner