Brief overview:

  • Crying is the infant’s way of communicating, and it signals a need that needs to be fulfilled.
  • Babies and toddlers are dependent on the comfort and care of their parents as they are unable to comfort themselves (self-soothing)
  • Sensitive response to the child’s signals is one of the most important factors in forming a secure attachment, especially when it comes to the child crying and other expressions of discomfort.
  • Secure attachment is one of the most important factors in relation to the healthy development of a child
  • Secure attachment can be seen as a form of resilience with regard to coping with crises, trauma, etc. later in life and has an impact on how the child regulates himself later in life, and what ways he can calm himself when faced with grief, pain or unrest.
  • Ignoring the child’s crying periodically may risk damaging the attachment
  • With objective measurements of the child’s sleep, there is no positive effect of sleep training, neither on the number of night awakenings nor the total amount of sleep
  • Few studies conclude that cry it out-sleep training does not harm attachment – a conclusion that stands in sharp contrast to basic research in attachment, that has shown a clear connection between sensitive response and attachment
  • 723 Danish psychologists signed an open letter in 2019 stating that a cry it out-sleep training method, known as the “good night and sleep well” method in Denmark (comparable to the Ferber-method, red.), should be discouraged, as such methods may risk the attachment and the child’s development. This view is shared by a wide range of foreign researchers, anthropologists, psychologists and more

Cry it out-sleep training can entail a number of risk factors for the child. One of the biggest concerns is the child’s attachment to the parents. Research in attachment theory has shown that sensitive response to the child’s signals is one of the most important factors in forming a secure attachment. In particular, response to the child’s crying and other expressions of discomfort have been shown to be important for attachment [5, 13, 15]. The child needs available adults at all hours of the day. When the child wakes up at night, it needs as much sensitive response as during the day. One study, for example, found an association between sensitive response at night and safe attachment [11]. Babies who were never or only occasionally comforted at night were at greater risk of insecure attachment. Periodic ignoring of the child’s crying may risk damaging the attachment.

Definition of cry it out-sleep training:

Cry it out (CIO) is defined as guidance that instructs parents to leave the child, even if it cries or screams when going to sleep. The child’s crying and/or screaming is ignored. The parents can either ignore the child for shorter or longer intervals or indefinitely. The criteria for cry it out are also met if the parents stay in the room with the child but reject or ignore the child’s attempts of contact, either consistently or at intervals.

In high-risk families, where the parents have few resources, there is a greater risk of insecure attachment [1]. This may be due, among other things, to the parents showing a lower degree of sensitive response. Interventions aimed at increasing parents’ sensitive response have been shown to increase the likelihood of a secure attachment [1]. This highlights the importance of supporting parents in being sensitive and accessible to their child. If, on the other hand, parents are encouraged to ignore their child’s signals when the child is going to sleep, there may be a risk of damaging the attachment. When parents are encouraged to be less accessible to their child at bedtime, there is also a risk that it will affect their overall approach to the child. If professionals tell parents that they can ignore their child’s crying or wait a while before responding to the child’s crying when the child goes to sleep, there is a risk that this approach will become part of the parents’ general approach to the child.

Babies and toddlers depend on the comfort and care of their parents as they are unable to calm themselves (self-soothe) [2]. Some parenting guides or self-help books encourage parents to let their child cry, claiming that this will teach the child to calm himself or herself, the much used term ‘self-soothing’. However, research clearly shows that this is not correct. Development of the ability for self-regulation happens in interaction with sensitive caregivers, who respond to the child’s emotional signals and help the child to regulate his emotions. A high degree of sensitive response leads to an improved ability of self-regulation [5]. Conversely, if a baby or child is repeatedly left to deal with difficult emotions for themselves, it can weaken the development of self-regulation [5].

Cry it out-sleep training often also entails that the child should sleep alone, which increases the risk of cot death in children under the age of one year [3,4]. It is safest for the baby to sleep in the same room as his parents, and it also makes it easier to breastfeed the baby [16]. During cry it out-sleep training, mothers are advised to refrain from breastfeeding the baby to sleep and restrict or completely stop breastfeeding at night. This can have negative consequences for the breastfeeding relationship, and it can lead to the cessation of breastfeeding completely [6].

There is no convincing evidence for the effect of sleep training on a child’s sleep. Some studies suggest a positive effect on a child’s sleep [17]. However, these are parent-reported studies. Some recent studies have included objective measurements of child sleep (actigraphy and video surveillance). In objective measurements of the child’s sleep, there is no positive effect, neither on the number of night awakenings nor the total amount of sleep [9,10,19].

Problems with research in the field

Some studies conclude cry it out-sleep training is not harmful to the child’s development and attachment. However, it is important to point out that several of these studies have a number of serious methodological weaknesses. For example, some studies concluding cry it out-sleep training does not harm attachment have not made use of objective measurements of attachment. Two studies conclude that cry it out-sleep training may actually have a positive effect on attachment  [7-8]. In these studies, however, a parent-reported measurement of attachment has been used, which may lead to results differing from those based on objective measurements.. Parental-reported measurements of sleep have also been used, and these measurements show that there has been a reduction in signaling behavior at night. The parents in the studies could have had a more positive view of their child and the relationship with the child as a result of the child not waking them up (as much) at night, and this may be a possible reason why the parent-reported measurements of attachment suggest that there has been an improvement in affiliation.

A study by Gradisar et al. (2016)  also conclude that cry it out-sleep training does not harm attachment. In this study, use has been made of objective measurements of attachment. The study found no difference in association between the intervention group and the control group one year after the intervention. However, the study has some limitations; there were only 14 participants in each group and the parents could choose to change groups at any time during the study, which two families did. Furthermore, there was no control for how the control group managed the children’s sleep, and the families in the control group may thus have chosen to try some form of cry it out-sleep training on their own [9].

There are few studies that conclude that cry it out-sleep training does not harm attachment. This conclusion is in sharp contrast to basic research in attachment, which has shown a clear connection between sensitive response and attachment.

There are only a few studies that have examined the long term wellbeing of the children. A RCT study by Lam, Hiscock and Wake (2003) found that three years after an intervention with cry it out-sleep training, there was no difference between children in the intervention group and the control group in terms of internalizing and externalizing behaviors [12]. An RCT study by Price, Wake, Okoumunne and Hiscock (2012) also found that five years after an intervention with cry it out-sleep training, there was no difference in emotional and behavioral problems in the children in the intervention group and the control group [18]. The study by Price et al. (2012) have, however, been criticized for lack of control over how the intervention group and the control group actually managed children’s sleep. The intervention group had only received instruction on how to use cry it out-sleep training, but the analysis did not take into account whether the parents had actually used the method or not. The parents in the control group may also have chosen to use cry it out-sleep training on their own, so it is not known whether there was in fact a difference in the handling of the children’s sleep in the two groups.

The studies of Lam et al. (2003) and Price et al., (2012) are used by some to conclude that cry it out-sleep training is not harmful to children’s development. However, this conclusion is based on a very flimsy basis, and it contrasts with what is otherwise known about children’s development. Basic research in developmental psychology has shown a positive correlation between sensitive response and the child’s development. As an example sensitive response leads to better emotion regulation, better social skills, and fewer behavioral problems [5,13]. Interventions such as cry it out-sleep training lead to a lower degree of sensitive response, and it can thus risk damaging the child’s development.

Researchers and professionals discourage cry it out-sleep training

Several international researchers agree that cry it out-sleep training can harm a child’s development. There are concerns that the child may become stressed during sleep training and that the lack of response from the parents may lead to social and emotional problems [20]. Researchers have also pointed out that cry it out-sleep training does not make sense in light of human evolution. The human child is 100% dependent on its caregivers to survive. Ignoring a crying child goes against the parents’ instinct, and the process is stressful for both the child and the parents [22]. The researchers point out that even if the parents go back to the child at regular intervals during sleep training, it can risk harming the child’s development. When the parents go back to the child and then leave it again, it merely gives the child false hopes, but not the comfort that the child longs for and needs [22].

The Australian Association for Infant Mental Health also advises against cry it out-sleep training [21]. It is highlighted, among other things, that crying is the infant’s way of communicating, and it signals a need that needs to be fulfilled. The infant is not capable of fulfilling his own needs, and it can cause emotional problems if the child’s needs are not adequately met. There is a concern that the child will learn that there is no point in seeking comfort from his or her caregivers. The baby will sooner or later stop crying, but this does not necessarily mean that the baby now is comfortable falling asleep alone. This is backed by a study that has shown elevated levels of stress hormone in babies who were sleep trained. By the third day of sleep training, most of the babies had stopped crying, but still elevated levels of stress hormone were seen [23]. The child may thus still be stressed and scared, even if it no longer cries, and this can be seen as an expression that the child has given up and as a result stopped signaling for help [21].

Denmark has many professionals who advise against cry it out-sleep training. In connection with a public debate on the book “Godnat og sov godt: Lær dit barn gode sovevaner” (“Duérmete, niño” (Sleep, Child. red.), a book containing advice comparable to the Ferber-method), more than 700 Danish psychologists signed an open letter stating that the “Godnat og sov godt” method from the book, should be discouraged, as such methods may risk attachment and the child’s development [24]. Babies and toddlers are unable to calm themselves and they are therefore deeply dependent on the comfort and reassurance of their caregivers. The psychologists also point out that it is normal for babies and young children to need help to fall asleep, just as it is normal for them to wake up at night and need the parents’ help to fall asleep again. This need will diminish over time, and it is not something that needs to be trained. Studies have also shown that sleep training does not lead to improvements in a child’s sleep [24].

References

  1. Letourneau, N., Tryphonopoulos, P., Giesbrecht, G., Dennis, C.,  Bhogal, S. &  Watson, B. (2015). Narrative and meta-analytic review of interventions aiming to improve maternal-child attachment security, Infant Mental Health, 36 (4), 366-387
  2. Berk, L. (2012). Child Development (9th. Ed.). Boston: Allyn and Bacon.
  3. Blair, P.S., Fleming, P.J., Smith, I.J., Platt, M., Young, J., Nadin, P., Berry, P. J., Golding, J. (1999). Babies sleeping with parents: Case-control study of factors influencing the risk of the sudden infant death syndrome. British Medical Journal, 319(7223), 1457-1461.
  4. Carpenter, R.G., Irgens, L.M., Blair, P.S., England, P.D., Fleming, P., Huber, J., Jorch, G., Schreuder, P. (2004). Sudden unexplained infant death in 20 regions in Europe: Case control study. Lancet, 363(9404), 185-191.
  5. Cassidy J. (1994). Emotion regulation: Influences of attachment relationships. Monographs of the Society for Research in Child Development, 59(2-3) 228-249.
  6. Douglas, P. & Hill, P. (2013). Behavioral sleep interventions in the first six months of life do not improve outcomes for mothers or infants: A systematic review. Journal of Developmental and Behavioral Pediatrics, 34(7) 497-507.
  7. France, K. G., (1992). Behavior characteristics and security in sleep-disturbed infants treated with extinction. Journal of Pediatric Psychology, 17(4), 467-475.
  8. France, K. G., Blampied, N. M. & Wilkinson, P. (1991). Treatment of infant sleep disturbance by trimeprazine in combination with extinction. Journal of Developmental and Behavioral Pediatrics, 12(5), 308-314.
  9. Gradisar, M., Jackson, K., Spurrier, N. J., Gibson, J., Whitham, J., Williams, A. S., Dolby, R. & Kennaway, D. (2016). Behavioral interventions for infant sleep problems: a randomized controlled trial. Pediatrics; 137(6), e20151486-e20151486.
  10. Hall, W. A., Hutton, E., Brant, R. F., Collet, J. P., Gregg, K., Saunders, R., Ipsiroglu, O., Gafni, A., Triolet, K., Tse, L., Bhagat, R. & Wooldridge, J. (2015). A randomized controlled trial of an intervention for infants’ behavioral sleep problems. BMC Pediatrics; 15(1), 181.
  11. Higley, E. & Dozier, M. (2009) Nighttime maternal responsiveness and infant attachment at one year. Attachment & Human Development, 11(4), 347-363.
  12. Lam, P., Hiscock, H. & Wake, M. (2003). Outcomes of infant sleep problems: a longitudinal study of sleep, behavior, and maternal well-being. Pediatrics, 111(3), 203-207.
  13. Leerkes, E. M. (2011). Maternal sensitivity during distressing tasks: A unique predictor of attachment security. Infant Behavior and Development, 34(3), 443-446.
  14. Leerkes, E. M., Blankson, A. N., & O’Brien, M. (2009). Differential effects of maternal sensitivity to infant distress and nondistress on social-emotional functioning. Journal of Abnormal Child Psychology, 80(3), 762-775.
  15. McElwain, N. L., & Booth-LaForce, C. (2006). Maternal sensitivity to infant distress and nondistress as predictors of infant–mother attachment security. Journal of Family Psychology, 20(2), 247–255.
  16. McKenna, J.J., & McDade, T. (2005). Why babies should never sleep alone: A review of the co-sleeping controversy in relation to SIDS, bedsharing and breast feeding. Paediatric Respiratory Reviews, 6(2), 134–152.
  17. Mindell, J. A., Kuhn, B., Lewin, D. S., Meltzer, L. J. & Sadeh, A (2006). Behavioral treatment of bedtime problems and night wakings in infants and young children. Sleep, 29(10), 1263-1276.
  18. Price, A. M. H, Wake, M., Okoumunne, O. C. & Hiscock, H. (2012). Five-Year Follow-up of Harms and Benefits of Behavioral Infant Sleep Intervention: Randomized Trial. Pediatrics, 130(4), 643-651.
  19. Stremler, R., Hodnett, E., Kenton, L., Lee, K., Weiss, S., Weston, J., Willan, A. (2013). Effect of behavioural-educational intervention on sleep for primiparous women and their infants in early postpartum: multisite randomised controlled trial. British Medical Journal, 346(7904), 1-14.
  20. https://videnskab.dk/krop-sundhed/forskere-advarer-mod-kontroversiel-soevntraening-derfor-skal-du-ikke-lade-dit-spaedbarn
  21. https://www.aaimhi.org/key-issues/position-statements-and-guidelines/AAIMHI-Position-paper-1-Controlled-crying.pdf
  22. https://www.bellybelly.com.au/baby-sleep/cry-it-out/
  23. Middlemiss, W., Granger, D. A., Goldberg, W. A. & Nathans, L. (2012). Asynchrony of mother-infant hypothalamic-pituitary-adrenal axis activity following extinction of infant crying responses induced during the transition to sleep. Early Human Development, 88(4), 227-232. 
  24. https://psykologernesbrev.dk/english