I am increasingly seeing the use of this Dr. Sears handout by AP/NPers as “proof” that CIO causes all sorts of harm – implying that if you CIO, your child is in danger of developing ADHD, losing precious IQ points, and becoming an ax-murdering psychopath. Examples can be seen in the comments here and here (note the poster of this link also previously invoked the notorious “Harvard Study”). Like my analysis of the aforementioned “Harvard Study” and the scientific rationale underlying the practice of CIO, I hope this will be of help to mainstream parents who feel overwhelmed by the list of sources (which, I promise you, none of the quoters have actually ever read) Doc Sears supposedly provides to support his position. I’ve found most of the sources on the ‘net, so you can peruse them yourselves and decide whether they actually say what Sears claims they do.
Let’s start with his opening paragraph (emphases mine):
Science tells us that when babies cry alone and unattended, they experience panic and anxiety. Their bodies and brains are flooded with adrenaline and cortisol stress hormones. Science has also found that when developing brain tissue is exposed to these hormones for prolonged periods these nerves won’t form connections to other nerves and will degenerate. Is it therefore possible that infants who endure many nights or weeks of crying-it-out alone are actually suffering harmful neurologic effects that may have permanent implications on the development of sections of their brain?
Since CIO (as in the Ferber method) does not typically last “many nights or weeks” nor do babies typically lie crying for “prolonged periods” (no, 5-15 minute stretches, though they may seem endless to anxious parents, do not qualify), this question is really moot. Sears would like to pretend that CIO involves months of endless crying, but the reality for most parents is a few nights of crying episodes which get shorter and shorter until the baby realizes that being put in bed means they need to sleep, which is, generally speaking, a week or two at most (if it doesn’t work by then, it’s probably time to try something else).
Chemical and hormonal imbalances in the brain
Research has shown that infants who are routinely separated from parents in a stressful way have abnormally high levels of the stress hormone cortisol, as well as lower growth hormone levels. These imbalances inhibit the development of nerve tissue in the brain, suppress growth, and depress the immune system. 5, 9, 11, 16
The first two references (5 and 9, respectively Butler et al and Kuhn et al) deal with rats of indeterminate age, whose endocrinology may or may not mimic those of human infants at 6+ months old. There is no report of any lasting damage, and the rat pups’ hormones restabilize once they’re returned to Mom – as would presumably happen with any separation for purposes of sleep in human babies.
Reference 11’s title is “Endocrine and Immune Responses to Separation and Maternal Loss in Non-Human Primates.”. I couldn’t find the book, but the title implies we’re talking about separations much longer (even as far as permanent separation) than human infants normally undergo when falling asleep.
Reference 16, Transition to child care: Associations with infant-mother attachment, infant negative emotion, and cortisol elevations, discusses elevation of stress hormone levels seen in 15-month-olds as a result of daycare attendance. As they point out, this is decidedly less stressful an event if the children are securely attached – which, to remind you, some 65% of American children are. Mind you, Young children adapt to repeated separations from their mothers, even of longer duration than a nights’ sleep. Mild, short stresses are not necessarily a bad thing.
Back to Doc Sears:
Researchers at Yale University and Harvard Medical School found that intense stress early in life can alter the brain’s neurotransmitter systems and cause structural and functional changes in regions of the brain similar to those seen in adults with depression. 17
Ref #17, “Effects of early stress on brain structure and function: implications for understanding the relationship between child maltreatment and depression, quite clearly deals with children who have been severely and consistently maltreated in early life, to the point where Social Services have to be involved. While some anti-CIO types would like to categorize the practice within the realm of child abuse/neglect, there is no evidence CIO in and of itself has any such effects – though Sears is desperately trying to conflate the two.
One study showed infants who experienced persistent crying episodes were 10 times more likely to have ADHD as a child, along with poor school performance and antisocial behavior. The researchers concluded these findings may be due to the lack of responsive attitude of the parents toward their babies. 14.
Actually, the study (which can be viewed full-text here) says nothing of the sort. The researchers looked at children who cried excessively at an average of 3 months (beyond the normal realm of colicky crying, and of course, having nothing to do with CIO nor, necessarily, maternal response to the crying); when they compared them to children who didn’t cry excessively at 8 and 10 years of age, they found 10/53 children in the persistent crying group had ADHD, vs. 1/62 control children. Their main hypothesis (supported by other studies they reference) is that persistent crying (and also sleeping and eating problems) may be an early sign of problems with emotional regulation, which may later manifest themselves as ADHD or school problems. This is emphatically NOT “CIO causes ADHD”, which is what Sears is implying. There is also no mention the researchers concluded that this was due to the lack of parental reponse to the persistently crying babies.
This is blatant misuse of a scientific source; though Sears is smart enough not to say outright that he thinks CIO causes ADHD, he leaves his foolish devotees to draw the “obvious” conclusion by the context.
Dr. Bruce Perry’s research at Baylor University may explain this finding. He found when chronic stress over-stimulates an infant’s brain stem (the part of the brain that controls adrenaline release), and the portions of the brain that thrive on physical and emotional input are neglected (such as when a baby is repeatedly left to cry alone), the child will grow up with an over-active adrenaline system. Such a child will display increased aggression, impulsivity, and violence later in life because the brainstem floods the body with adrenaline and other stress hormones at inappropriate and frequent times. 6
Refrence #6 can be found in its entirety here. I really shouldn’t have to say this, but it quite obviously doesn’t discuss CIO – rather cases of severe abuse, neglect and regular battery of infants which bring about the “chronic stress” and the subsequent adverse events described.
Dr. Allan Schore of the UCLA School of Medicine has demonstrated that the stress hormone cortisol (which floods the brain during intense crying and other stressful events) actually destroys nerve connections in critical portions of an infant’s developing brain. In addition, when the portions of the brain responsible for attachment and emotional control are not stimulated during infancy (as may occur when a baby is repeatedly neglected) these sections of the brain will not develop. The result – a violent, impulsive, emotionally unattached child. He concludes that the sensitivity and responsiveness of a parent stimulates and shapes the nerve connections in key sections of the brain responsible for attachment and emotional well-being. 7, 8
The interview with Dr. Schore (which can be found here) does say, “The baby left alone to cry or whose cries result in unpredictable or abusive responses may never learn what it feels like to maintain or regain balance through thoughtfully timed external soothing.” . However, the context is about children who are regularly shamed or ignored (day and night), and thus experience dampening of the neural pathways for expressing emotion and empathy. There is no evidence presented that normal, otherwise securely attached children undergo this simply as a result of CIO. In fact, the example given in the previous chapter (Rachel) is clearly a little girl who has been badly abused and neglected.
Decreased intellectual, emotional, and social development
Infant developmental specialist Dr. Michael Lewis presented research findings at an American Academy of Pediatrics meeting, concluding that “the single most important influence of a child’s intellectual development is the responsiveness of the mother to the cues of her baby.”
Researchers have found babies whose cries are usually ignored will not develop healthy intellectual and social skills. 19
Another reference I can’t access online, but since Dr. Zeanah is an expert on attachment-disordered children, I would guess this does not refer to children who are merely CIO’ed – whose cries are not “usually ignored”, or even ignored at all (as per the Ferber method).
Dr. Rao and colleagues at the National Institutes of Health showed that infants with prolonged crying (but not due to colic) in the first 3 months of life had an average IQ 9 points lower at 5 years of age. They also showed poor fine motor development. (2)
*Sigh* Here’s Rao et al. This is the same sort of inference Sears is trying to push on his groupies as the “CIO causes ADHD study”. In fact, Rao states rather clearly:”We speculate that irritability caused by subtle underlying neurological problems may be the cause of prolonged crying, despite the fact that most common neurological problems were ruled out in our population. Alternatively, children normally cry less as they mature developmentally; thus prolonged crying may be a sign of
delayed maturation.”. Ergo, the persistent crying (not CIO) may be an early sign the child may have congenital neurological issues which may manifest themselves later. So no, CIO doesn’t cause your child’s IQ to drop.
Researchers at Pennsylvania State and Arizona State Universities found that infants with excessive crying during the early months showed more difficulty controlling their emotions and became even fussier when parents tried to consol [sic] them at 10 months. 15
Ditto. In fact, according to the abstract of Ref #15, the mothers’ behavior had nothing to do with the children’s emotional state: “Maternal behavior and ratings of temperament at 5 and 10 months failed to distinguish the 2 cry groups.”
Other research has shown that these babies have a more annoying quality to their cry, are more clingy during the day, and take longer to become independent as children 1.
Said “other research” is a non-peer reviewed, unpublished Master’s thesis. Can we say “grasping at straws”?
Harmful physiologic changes
Animal and human research has shown when separated from parents, infants and children show unstable temperatures, heart arrhythmias, and decreased REM sleep (the stage of sleep that promotes brain development). 10 12, 13
As far as I can tell, all of the studies referenced deal with animals (I suspect Sears didn’t actually read them, because the author of ref #12 is also the author of #13, and the source is misquoted). Is he seriously contending human babies “show unstable temperatures, heart arrhythmias, and decreased REM sleep” whenever they’re away from their parents? Babies should be dropping like files if this were happening.
Dr. Brazy at Duke University and Ludington-Hoe and colleagues at Case Western University showed in 2 separate studies how prolonged crying in infants causes increased blood pressure in the brain, elevates stress hormones, obstructs blood from draining out of the brain, and decreases oxygenation to the brain. They concluded that caregivers should answer cries swiftly, consistently, and comprehensively. (3) and (4)
Both articles (only Brazy – ref #3 – is a study; Ludington-Hoe – ref #4 – is a review) deal with newborn babies. So just for the record, you heard it from me first, folks: DO NOT CIO YOUR NEWBORNS. ‘Kay?
I will point out that crying only decreased cerebral oxygenation (to a dangerous level? We don’t know) in infants with respiratory problems, not in normal newborns. That’s a fact not revealed to us by Sears.
However, as Ludington-Hoe states, there’s the fact that crying is “a series of four movements that basically resembles a Valsalva maneuver”. The Valsalva Maneuver is described as “A maneuver in which a person tries to exhale forcibly with a closed glottis (the windpipe) so that no air exits through the mouth or nose as, for example, in strenuous coughing, straining during a bowel movement, or lifting a heavy weight.”. The pressures are expected to be lower in crying than in a true Valsalva, as the glottis is not fully closed – evidenced by the piercing wails emerging from it. I can find no evidence of crying-induced cerebral hemorrhages in infants, which would indicate that the cerebral blood pressure during crying does not climb to dangerous levels. In any case, the infant’s flexible skull sutures apparently help prevent dangerous rises in cerebral pressure by stretching and releasing the pressure.
Either way, we don’t try to stop all coughing and defecation in infants with this rationale; there’s no reason to invoke it to stop all crying, either (I’m sure parents of colicky infants will be much reassured now).
There is an unused reference (#18) in the list. I’m sure you can figure out why it, too, does not prove CIO can harm babies. ;)
Filed under: Infant sleep