Is sleep training harmful? What the Australian studies found

Short answer: For babies over 6 months, the best evidence says no. A Melbourne trial that followed families to age 6 found no differences in emotional health, behaviour, stress or the parent and child relationship, and an Adelaide trial found no attachment harms. Under 6 months is different. A systematic review found structured methods haven't been shown to help and may carry risks.

This question carries a lot of guilt, and a lot of strong opinions online. Here's what the studies actually measured.

Over 6 months: the long-term studies

Some of the best research in the world on this comes from Australia.

• Melbourne, 2002. 156 mothers of babies aged 6–12 months. Two months later, more sleep problems had resolved in the group taught settling techniques (53 of 76 against 36 of 76). Mothers with high depression scores improved ^[1].
• Melbourne, 2007 and 2008. 328 mothers across 49 maternal and child health centres. Fewer sleep problems at 10 months (56% against 68%) and 12 months (39% against 55%). At 2 years, fewer mothers had depression symptoms, with no harm to parenting or child mental health ^[2][3].
• The five-year follow-up, 2012. 225 of those families, with children now aged 6. The researchers found "no evidence of differences… for any outcome", including emotional health, behaviour, chronic stress, closeness and conflict, and maternal mental health ^[4].
• Adelaide, 2016. 43 babies aged 6–16 months. Both graduated extinction and bedtime fading helped. Stress hormone levels went slightly down, not up, and there were no attachment differences at 12 months. It was a small trial, and cortisol wasn't measured during the night itself ^[5].

Across 52 studies, an American task force found 94% reported these methods worked, with over 80% of children improving for 3–6 months ^[6].

Under 6 months is different

A systematic review found that structured sleep methods in the first six months "have not been shown to decrease infant crying, prevent sleep and behavioral problems in later childhood, or protect against postnatal depression", and listed possible risks, including more crying, early weaning and higher SIDS risk if a baby sleeps in a separate room ^[7]. Red Nose recommends your baby sleeps in your room for at least the first 6 months ^[8].

Gentlest first

You don't have to choose between doing nothing and leaving your baby to cry.

• Responsive settling. Comfort your baby and gradually reduce the help: feeding to drowsy, then rocking, then patting, then your voice. Raising Children Network says it takes "3 days to 3 weeks" ^[9].
• Bedtime fading. Start bedtime at the time your child currently falls asleep, then move it 15 minutes earlier every few days ^[10].
• Camping out. Stay in the room and move a little further away over time ^[2].
• Controlled comforting. Check in at gradually longer intervals ^[5].

A sleep consultant or child health nurse can help you pick one that suits your child and your family, and stick with it.

Sources

1. Hiscock H, Wake M. Randomised controlled trial of behavioural infant sleep intervention. BMJ 2002;324:1062–5.
2. Hiscock H et al. Improving infant sleep and maternal mental health: a cluster randomised trial. Arch Dis Child 2007;92(11):952–8.
3. Hiscock H et al. Long-term mother and child mental health effects of a population-based infant sleep intervention. Pediatrics 2008;122(3):e621–7.
4. Price AMH et al. Five-year follow-up of harms and benefits of behavioral infant sleep intervention. Pediatrics 2012;130(4):643–51.
5. Gradisar M et al. Behavioral interventions for infant sleep problems: a randomized controlled trial. Pediatrics 2016;137(6):e20151486.
6. Mindell JA et al. Behavioral treatment of bedtime problems and night wakings in infants and young children. Sleep 2006;29(10):1263–76.
7. Douglas PS, Hill PS. Behavioral sleep interventions in the first six months of life. J Dev Behav Pediatr 2013;34(7):497–507.
8. Red Nose Australia. The six safe sleep recommendations. rednose.org.au/safe-sleep-and-safer-pregnancy/pregnancy-to-b…
9. Raising Children Network. Responsive settling: 6–18 months. raisingchildren.net.au/babies/sleep/settling-routines/respon…
10. Raising Children Network. Bedtime fading. raisingchildren.net.au/babies/sleep/settling-routines/bedtim…

Quick questions

Does controlled comforting damage attachment?

An Adelaide randomised trial of 43 babies aged 6–16 months found no differences in attachment or emotional and behavioural problems at 12 months after graduated extinction or bedtime fading. It was a small study, so it adds to the evidence rather than settling it alone.

Can I sleep train a 4 month old?

A systematic review of behavioural sleep methods in the first six months found they haven't been shown to reduce crying or prevent later problems, and may carry risks. Under 6 months, the focus is safe sleep and comforting your baby to sleep.

What are the gentlest settling options?

Responsive settling, where you comfort your baby and slowly reduce how much help you give, and bedtime fading, where you start bedtime at the time your child falls asleep and move it earlier by 15 minutes every few days.