Sleep Training and Mental Health
Those promoting sleep training - techniques designed to modify natural sleep behaviour in infants - often state the benefit for parents.
When babies cry - known as signaling - their mother’s body reacts with an increase in the hormone cortisol. Cortisol is sometimes referred to as the “stress” hormone. When the mother is startled awake by her baby crying, this surge drives her to quickly attend to them. The baby stops crying as their needs are met and the mother’s cortisol levels return to normal.
Babies also experience a surge of cortisol during crying. Any delay in the mother responding to their crying means a longer period in this stressed state. Once a baby stops crying because their needs are met, their cortisol level naturally returns to normal.
Co-sleeping - bed sharing and room-sharing - minimises the time between an infant beginning to wake and their mother responding. The baby might not even reach the crying stage of feeding cues and both mother and baby remain in a low-cortisol state. Babies who spend the night in a separate room from their mother might quickly reach the crying stage, as the more subtle feeding cues are not observed by the mother asleep in another part of the house.
Sleep training based on “extinction methods” (often referred to as controlled crying or controlled comforting) work by parents delaying their response to the baby and gradually extending the time before they go to them, with the goal being the baby “self soothes”, stops crying and returns to sleep without parental support.
Studies of these methods have shown positive outcomes for adults: as the baby stops crying, the mother’s cortisol levels drop and they can quickly return to sleep. They report better mood and it is generally considered to improve adult mental health.
However, the full details of these studies are not always reported. Video observation in the infant’s room shows a very different picture to what the parents suppose: the baby has not resumed sleep in many cases.
You might be familiar with the “Fight or Flight Responses” - when confronted with danger, our brain has to quickly decide whether to remain and defend ourselves or to run away as quickly as possible. Cortisol plays an important role in these responses. Less well-known are the other two trauma responses which might come into play: “Fawn or Freeze”
Fawning is when a victim attempts to make an attacker happy or befriend them, in the hope they will not be injured or killed.
Freezing is when the brain goes into survival mode and stops all voluntary body movements and becomes still.
When a baby senses it's signaling is not bringing the attention of their mother, their primal reaction is to signal more loudly. But after a short period of time, they move instead to a different focus: self-preservation. Crying burns valuable energy and attracts unwanted attention. The infant becomes quiet and still. Their eyes remain open and they are alert. As far as they can understand, they have been abandoned and no adult is coming.
Studies looking at the infant experience of controlled crying found that crying at bedtime ceased by around the third night. Cortisol levels however, remained as high as the level recorded on the first night. The baby has not learned to “self settle”. They have given up seeking support. On high alert in the Freeze state, the baby eventually falls asleep through exhaustion.
The Australian Association for Infant Mental Health Ltd (AAIMH) is a not-for-profit organisation of professionals from a range of disciplines including health, education and welfare dedicated to the field of infant mental health.
AAIMH’s primary focus is to draw attention to the importance of the healthy social and emotional development of infants (0 to 3 years) in Australia.
This is achieved by assisting families, professionals and communities to build nurturing and strong relationships with their children, and to be aware of the causes and signs of mental, physical and emotional stress in infants.
AAIMH’s position – Extinction Based Behavioral Sleep Interventions
AAIMH is concerned that extinction based behavioural sleep interventions are not consistent with the infant’s needs for optimal emotional and psychological health and may have unintended negative consequences. Extinction based behavioural sleep interventions have not been rigorously assessed in terms of the impact on the infant’s emotional development. While arguably there is evidence to suggest these techniques do not harm infants, this does not mean there is evidence of no harm.
What are the long-term outcomes?
How does this heightened cortisol level impact development and the mental health of the child in later life? The short answer is - we don’t know. Nobody has done the research.
Conclusion
Without evidence that extinction methods of sleep training do no harm, we cannot say they are safe.
In an emergency, call 000.
Help is available 24 hours a day, 7 days a week, anywhere in Australia. If you need help now, call:
Lifeline – 13 11 14
Kids Helpline – 1800 55 1800
Beyond Blue – 1300 224 636.
PANDA 1300 726 306
As many as 1 in 5 expecting or new mums and 1 in 10 expecting or new dads will experience perinatal anxiety or depression. Perinatal anxiety or depression affects around 100,000 families across Australia every year.
Around 8.6 million or 43.7% of Australians aged 16-85 had experienced a mental health disorder at some point in their life, according to the 2020-21 National Study of Mental Health and Wellbeing.
