November 24, 2009 — The first study to thoroughly examine the relationship between depression in mothers and asthma in their children found that a mother's depression can worsen, and is not the result of, her child's asthma.
The study, by Michiko Otsuki, PhD, from the University of South Florida in St. Petersburg, who was a behavioral medicine fellow at Johns Hopkins Children's Center in Baltimore, Maryland, at the time of the study, and colleagues from Johns Hopkins, was published online October 22 in the Journal of Pediatric Psychology.
Senior investigator Kristin A. Riekert, PhD, assistant professor and codirector of the Johns Hopkins Adherence Research Center, Division of Pulmonary Critical Care Medicine, told Medscape Psychiatry, they were surprised that asthma symptoms did not predict maternal depressive symptoms.
"Since we recruited children at a point of high symptoms during an emergency department visit, the results might have been different in children with less severe asthma," Dr. Riekert noted. "However, children with frequent emergency department visits have more severe asthma and use more healthcare, so paying attention to maternal depression with this population could make a big difference."
E. Sherwood Brown, MD, PhD, associate professor of psychiatry at the University of Texas Southwestern Medical Center in Dallas, who reviewed the study for Medscape Psychiatry, agreed.
"I find the data very interesting," he said. "A question researchers struggle with is the direction of the relationship between maternal depression and childhood asthma symptoms and/or service utilization. It is intuitive to suggest that mothers of children with worsening asthma might get depressed due to stress from the illness and burden of care," he noted.
However, "this study suggests that the relationship may be more complex and that maternal depressive symptoms may predict the severity of the child's asthma symptoms," Dr. Brown added. "These findings suggest that effective interventions for the mother's depression could result in improvement in the child's asthma symptoms."
Reciprocal Effects
The Hopkins researchers analyzed data gathered as part of a randomized controlled trial of an intervention aimed at reducing emergency department use among high-risk inner-city children with asthma. Participants were recruited by weekly review of emergency department records.
The investigators then analyzed data from interviews with 262 mothers of African American children with asthma to test 4 hypotheses: (1) a "reciprocal effects" model in which maternal depressive symptoms and child asthma morbidity at time 1 would simultaneously predict subsequent child asthma morbidity and maternal depressive symptoms; (2) a "depressive symptoms effect model" in which maternal depressive symptoms would predict subsequent child asthma morbidity; (3) an "asthma morbidity effects model" in which child asthma morbidity would predict subsequent maternal depressive symptoms; and (4) the null hypothesis.
Maternal depressive symptoms were assessed by telephone using an abridged, 11-item version of the Center for Epidemiological Studies Scale.
The analysis showed that children whose mothers had more depressive symptoms had more frequent asthma symptoms during the 6 months of the study and that children whose mothers reported fewer depressive symptoms had less frequent asthma symptoms. The child's asthma severity did not predict later maternal depressive symptoms, however. This finding suggests that maternal depression is an independent risk factor for children's asthma severity.
"Even though our research was not set up to measure just how much a mom's depression increased the frequency of her child's symptoms, a clear pattern emerged in which the latter followed the earlier," Dr. Riekert said. "Intuitively, it may seem that we're dealing with a chicken-egg situation, but our study suggests otherwise. The fact that mom's depression was not affected by how often her child had symptoms really caught us off guard, but it also suggested which factor comes first."
A Red Flag
The researchers did not study why and how a mother's depression affects a child's asthma status, but because depression often involves fatigue, memory lapses, and difficulty concentrating, they suggest that it might affect a parent's ability to manage the child's chronic condition.
"Mom is the one who must implement the doctor's recommendations for treatment and follow-up, and if she is depressed she can't do it well, so the child will suffer," said Dr. Otsuki.
The investigators say their findings should prompt pediatricians who treat children with asthma to pay close attention to the child's primary caregiver — whether or not it is the mother — and screen and refer them for treatment if needed.
"We ask these parents if they are smokers all the time, so maybe it's time to start asking them if they are coping well emotionally," said coinvestigator Arlene Butz, ScD, a pediatric asthma specialist at Johns Hopkins Children's Center. "Doctors are trained to pick up on subtle clues, so if they see a red flag in mom, they should follow up with a depression screener and referral if needed."
This study was funded by the National Heart, Lung, and Blood Institute. Dr. Otsuki, Dr. Riekert, Dr. Brown, and Dr. Butz have disclosed no relevant financial relationships.
J Pediatr Psychol. Published online October 22, 2009.
