First, Do No Harm: A Critique of Recent Research on “Controlled Crying” (Part 1)

Today, we present Part 1 of a commentary from Kathleen Kendall-Tackett on a recent study about the long-term effects of controlled-crying for infants. As infant sleep and breastfeeding are so closely tied together, we are so glad to share this with our readers. Check back on Thursday for Part 2.

By Kathleen Kendall-Tackett, Ph.D., IBCLC, FAPA 

A recent article in Pediatrics (Price, Wake, Ukoumunne, & Hiscock, 2012) reported on the long-term effects of a controlled-crying intervention for parents of infants 8 to 10 months old. The children were assessed five years post-intervention and showed no apparent harm. The media response to these findings has been overwhelming. Could this be the answer that weary parents have been waiting for? The authors certainly thought so. In fact, they concluded that practitioners could “confidently” recommend this approach.

Before we proceed, let’s step back and consider whether this recommendation is warranted. We must critically evaluate both the current study and where it fits within the larger literature in maternal-child health. In my view, there are a number of serious limitations to this study that call into question whether we should recommend this practice to parents.

Study Limitations

The Cumulative Effect of Childhood Adversities

Context is important to consider when evaluating potential harm caused by a parenting technique. In other words, how many parental missteps does it take for children to show evidence of lasting harm? Fortunately, children are resilient and don’t require perfect parenting. However, chronic bad parenting does harm children and the effects are cumulative (Centers for Disease Control and Prevention, 2010).

So does controlled crying cause infant harm? If it occurs in families with generally warm, responsive, and loving parents, probably not. I am more concerned about the impact of controlled crying when it takes place in high-risk families. A full 31% of the Price et al. original sample was lost to follow-up, most of them “high disadvantage.” In other words, the group most likely to be negatively affected by controlled crying was not in the follow-up study.

Assessing “Dose”: The Chronicity and Severity of the Experience

When assessing potential harm of a practice, it’s also important to consider chronicity and severity. This is a way of factoring in “dose” of an intervention. In terms of infant sleep, we need to know how often controlled crying was used in an average week, how many weeks or months that the parents employed these techniques, and in an average episode how many minutes elapsed before the parents responded to their babies. The longer they used it, the more pronounced the effects.

Information about “dose” was totally absent from the Price et al. study. From their article, we know little about what the parents actually did in either the intervention or control group. Even beyond the research protocol, parents could have implemented a controlled-crying program for themselves. We have no way of knowing. Given the wide range of practices that likely occurred in both the “intervention” and “control” groups, I am again not surprised to see no significant difference between groups.

Was the Intervention Actually Effective, Even in the Short Term?

Another problematic aspect of this study has to do with the research design’s inability to account for the Hawthorne Effect. The Hawthorne Effect was first noted by industrial psychologists who were testing the impact of minute changes in illumination on productivity in factory workers. When they raised the level, productivity increased. When they lowered the level, productivity also increased. In other words, any intervention was described as helpful. It’s basically a placebo effect for behavioral interventions.

The Hawthorne Effect could also be behind the positive results for the controlled-crying intervention. In earlier articles, the authors reported that controlled crying lowered rates of maternal depression and improved infant sleep. Did it? Perhaps it was simply a matter of the mothers having someone to listen to their concerns. A better test would have been to compare it to another intervention (such as educating mothers about the developmental normality of infant waking at 8 to 10 months, and brainstorming about ways the mothers could get more rest and cope with fatigue).

Check back on Thursday for Part 2 of this commentary. 

Kathleen Kendall-Tackett, Ph.D., IBCLC, FAPA is a health psychologist and board-certified lactation consultant. She has authored or edited 22 books and more than 320 articles on family violence, postpartum depression, breastfeeding, and women’s health. Dr. Kendall-Tackett is a research associate at the Crimes against Children Research Center at the University of New Hampshire and a clinical associate professor of pediatrics at Texas Tech University School of Medicine in Amarillo, Texas. She is a Fellow of the American Psychological Association, and is president-elect of the APA Division of Trauma Psychology. You can view her website at www.KathleenKendall-Tackett.com.