I am copying and pasting two articles from the Attachment Parenting list-serve I belong to. The first article is about the harmful effects of crying (it out) on babies’ brain and development. The second piece is about the benefits of co-sleeping for babies. Read on!
Science Says: Excessive Crying Could Be Harmful to Babies
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? Here is how
science answers this alarming question:
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
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
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.
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
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
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
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)
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 them at 10 months. 15
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.
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
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)
P. Heron, “Non-Reactive Cosleeping and Child Behavior: Getting a Good
Night’s Sleep All Night, Every Night,” Master’s thesis, Department of
Psychology, University of Bristol, 1994.
M R Rao, et al; Long Term Cognitive Development in Children with Prolonged
Crying, National Institutes of Health, Archives of Disease in Childhood
2004; 89:989-992.
J pediatrics 1988 Brazy, J E. Mar 112 (3): 457-61. Duke University
Ludington-Hoe SM, Case Western U, Neonatal Network 2002 Mar; 21(2): 29-36
Butler, S R, et al. Maternal Behavior as a Regulator of Polyamine
Biosynthesis in Brain and Heart of Developing Rat Pups. Science 1978,
199:445-447.
Perry, B. (1997), “Incubated in Terror: Neurodevelopmental Factors in the
Cycle of Violence,” Children in a Violent Society, Guilford Press, New York.
Schore, A.N. (1996), “The Experience-Dependent Maturation of a Regulatory
System in the Orbital Prefrontal Cortex and the Origen of Developmental
Psychopathology,” Development and Psychopathology 8: 59 - 87.
Karr-Morse, R, Wiley, M. Interview With Dr. Allan Schore, Ghosts From the
Nursery, 1997, pg 200.
Kuhn, C M, et al. Selective Depression of Serum Growth Hormone During
Maternal Deprivation in Rat Pups. Science 1978, 201:1035-1036.
Hollenbeck, A R, et al. Children with Serious Illness: Behavioral Correlates
of Separation and Solution. Child Psychiatry and Human Development 1980,
11:3-11.
Coe, C L, et al. Endocrine and Immune Responses to Separation and Maternal
Loss in Non-Human Primates. The Psychology of Attachment and Separation, ed.
M Reite and T Fields, 1985. Pg. 163-199. New York: Academic Press.
Rosenblum and Moltz, The Mother-Infant Interaction as a Regulator of Infant
Physiology and Behavior. In Symbiosis in Parent-Offspring Interactions, New
York: Plenum, 1983.
Hofer, M and H. Shair, Control of Sleep-Wake States in the Infant Rat by
Features of the Mother-Infant Relationship. Developmental Psychobiology,
1982, 15:229-243.
Wolke, D, et al, Persistent Infant Crying and Hyperactivity Problems in
Middle Childhood, Pediatrics, 2002; 109:1054-1060.
Stifter and Spinrad, The Effect of Excessive Crying on the Development of
Emotion Regulation, Infancy, 2002; 3(2), 133-152.
Ahnert L, et al, Transition to Child Care: Associations with Infant-mother
Attachment, Infant Negative Emotion, and Cortisol Elevations, Child
Development, 2004, May-June; 75(3):649-650.
Kaufman J, Charney D. Effects of Early Stress on Brain Structure and
Function: Implications for Understanding the Relationship Between Child
Maltreatment and Depression, Developmental Psychopathology, 2001 Summer;
13(3):451-471.
Teicher MH et al, The Neurobiological Consequences of Early Stress and
Childhood Maltreatment, Neuroscience Biobehavior Review 2003, Jan-Mar;
27(1-2):33-44.
Leiberman, A. F., & Zeanah, H., Disorders of Attachment in Infancy, Infant
Psychiatry 1995, 4:571-587.
———————————————
Scientific Benefits of Co-sleeping
Popular media has tried to discourage parents from sharing sleep with their
babies, calling this worldwide practice unsafe. Medical science, however,
doesn’t back this conclusion. In fact, research shows that co-sleeping is
actually safer than sleeping alone. Here is what science says about sleeping
with your baby:
Sleep more peacefully
Research shows that co-sleeping infants virtually never startle during sleep
and rarely cry during the night, compared to solo sleepers who startle
repeatedly throughout the night and spend 4 times the number of minutes
crying 1. Startling and crying releases adrenaline, which increases heart
rate and blood pressure, interferes with restful sleep and leads to long
term sleep anxiety.
Stable physiology
Studies show that infants who sleep near to parents have more stable
temperatures 2, regular heart rhythms, and fewer long pauses in breathing
compared to babies who sleep alone 3. This means baby sleeps physiologically
safer.
Decreases risk of Sudden Infant Death Syndrome
Worldwide research shows that the SIDS rate is lowest (and even unheard of)
in countries where co-sleeping is the norm, rather than the exception 4, 5,
6, 7, 8, 9. Babies who sleep either in or next to their parents’ bed have a
fourfold decrease in the chance of SIDS 10. Co-sleeping babies actually
spend more time sleeping on their back or side 1 which decreases the risk of
SIDS. Further research shows that the carbon dioxide exhaled by a parent
actually works to stimulate baby’s breathing 11.
Long term emotional health
Co-sleeping babies grow up with a higher self-esteem, less anxiety, become
independent sooner, are better behaved in school 12, and are more
comfortable with affection 13. They also have less psychiatric problems 14.
Safer than crib sleeping
The Consumer Product Safety Commission published data that described infant
fatalities in adult beds. These same data, however, showed more than 3 times
as many crib related infant fatalities compared to adult bed accidents 15.
Another recent large study concluded that bed sharing did NOT increase the
risk of SIDS, unless the mom was a smoker or abused alcohol 16.
McKenna, J., et al, “Experimental studies of infant-parent co-sleeping:
Mutual physiological and behavioral influences and their relevance to SIDS
(sudden infant death syndrome).” Early Human Development 38 (1994)187-201.
C. Richard et al., “Sleeping Position, Orientation, and Proximity in
Bedsharing Infants and Mothers,” Sleep 19 (1996): 667-684.
Touch in Early Development, T. Field, ed. (Mahway, New Jersey: Lawrence
Earlbaum and Assoc., 1995).
“SIDS Global Task Force Child Care Study” E.A.S. Nelson et al., Early Human
Development 62 (2001): 43-55
A. H. Sankaran et al., “Sudden Infant Death Syndrome and Infant Care
Practices in Saskatchewan, Canada,” Program and Abstracts, Sixth SIDS
International Conference, Auckland, New Zealand, February 8-11, 2000.
D. P. Davies, “Cot Death In Hong Kong: A Rare Problem?” The Lancet 2 (1985):
1346-1348.
N. P. Lee et al., “Sudden Infant Death Syndrome in Hong Kong: Confirmation
of Low Incidence,” British Medical Journal 298 (1999): 72.
S. Fukai and F. Hiroshi, “1999 Annual Report, Japan SIDS Family
Association,” Sixth SIDS International Conference, Auckland, New Zealand,
2000.
E. A. S. Nelson et al., “International Child Care Practice Study: Infant
Sleeping Environment,” Early Human Development 62 (2001): 43-55.
P. S. Blair, P. J. Fleming, D. Bensley, et al., “Where Should Babies Sleep -
Along or With Parents? Factors Influencing the Risk Of SIDS in the CESDI
Study,” British Medical Journal 319 (1999): 1457-1462.
SIDS book, page 227, #162
P. Heron, “Non-Reactive Cosleeping and Child Behavior: Getting a Good
Night’s Sleep All Night, Every Night,” Master’s thesis, Department of
Psychology, University of Bristol, 1994.
M. Crawford, “Parenting Practices in the Basque Country: Implications of
Infant and Childhood Sleeping Location for Personality Development” Ethos
22, no 1 (1994): 42-82.
J. F. Forbes et al., “The Cosleeping Habits of Military Children,” Military
Medicine 157 (1992): 196-200.
D. A. Drago and A. L. Dannenberg, “Infant Mechanical Suffocation Deaths in
the United States, 1980-1997,” Pediatrics 103, no. 5 (1999): e59.
R. G. Carpenter et al., “Sudden Unexplained Infant Death in 20 Regions in
Europe: Case Control Study,” Lancet 2004; 363: 185-191.
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