The Cry It Out Method: How It Works and the Evidence

The cry it out method, in its strict form, means putting your baby down awake and not returning until morning, apart from safety and feeds you have decided to keep. Sleep researchers call this full or unmodified extinction. It is the most misunderstood and most argued-about approach in baby sleep.

It is worth being precise, because “cry it out” is used loosely for anything involving tears. True extinction has no timed check-ins, which is what separates it from the Ferber method, where you return at set intervals. This guide lays out what the method actually is, what the evidence shows about whether it works, and, just as important, what the evidence does and does not show about harm.

What “Cry It Out” Actually Means

The phrase gets thrown at any method that involves crying, which muddies the conversation. In the research, cry it out means full or unmodified extinction: after a calm bedtime routine, you put your baby down awake, say goodnight, and do not return until morning, except to keep your baby safe or to give feeds you have chosen to continue.¹

Method	What you do	Also called
Cry it out	Put down awake, do not return until morning (bar safety/feeds)	Full or unmodified extinction
Ferber	Return at progressively longer timed intervals to briefly reassure	Graduated extinction, controlled crying
Chair method	Stay in the room, sit by the crib, move farther away over nights	Camping out, gradual retreat
Bedtime fading	Temporarily move bedtime later to match natural sleep onset	Faded bedtime

So if you have read our Ferber method guide and pictured timed check-ins, that is not cry it out. The absence of check-ins is the defining feature here.

What the Evidence Shows About Whether It Works

On effectiveness, the evidence is actually strong and fairly consistent. A major review by the American Academy of Sleep Medicine looked across dozens of studies and found behavioral interventions effective in the large majority, with unmodified extinction among the best-supported approaches.¹ A later meta-analysis reached similar conclusions.¹⁰

The benefits are not only about the baby. In randomized trials, behavioral sleep intervention improved infant sleep and, notably, reduced symptoms of maternal depression. One trial found sleep problems resolved in far more intervention families at two months, and a follow-up found lower rates of maternal depression at age 2.⁴⁵

Results usually show up fast, within a week or two, though the first few nights are typically the hardest and crying can briefly spike before it improves.

The Harm Question, Honestly

This is the reason the method is so contested, and it is where the internet is least honest in both directions. Let us take the two overreaching claims in turn.

The claim that cry it out floods a baby with cortisol and damages attachment traces almost entirely to one small study. It followed 25 infants in an inpatient sleep program, had no control group, and sampled cortisol on just two days. It reported that babies stopped showing distress before their cortisol settled. It was widely criticized on methodological grounds, and it did not measure anything like brain damage. It cannot support a strong harm claim.⁶

The opposite claim, that cry it out is proven completely safe, also overreaches. The best randomized trial found no differences in cortisol, attachment, or behavior at a 12-month follow-up, which is reassuring, but it had only about 14 infants per group for those measures, too few to prove safety.² The strongest long-term evidence is a five-year follow-up of 326 children that found no difference on any measured outcome, including stress, behavior, and the parent-child relationship, at age 6.³ A separate study of infants left to cry it out found no adverse effect on attachment or behavior at 18 months.⁷

The honest bottom line: there is no good evidence that cry it out causes lasting harm, and real evidence it helps sleep and maternal mood in the short term. But “no evidence of harm” is not the same as “evidence of no harm,” and the safety studies are small. Both the alarmist and the absolutist versions of this debate are ahead of the data.

How Many Babies This Is Relevant To

Cry it out targets sleep-onset associations, the ways a baby has learned to fall asleep with help. Our State of Baby Sleep 2026 report, a survey of 74,379 parents across 112 countries, shows how widespread those associations are.

How babies actually fall asleep

Feeding and rocking dominate; independent sleep onset is rare

Feeding

63.9%

Rocking

60.3%

It depends

19.3%

Alone

9.7%

63.9 percent of babies are fed to sleep, 60.3 percent are rocked, and fewer than 1 in 10 fall asleep on their own. That is the pattern any sleep-training method is working to change. It also explains why so many families consider it, and why none of them should feel like an outlier for doing so.

Who It Suits, and the Gentler Alternatives

Cry it out is not a newborn technique. Babies do not have settled sleep cycles until around 4 months, and essentially every trial enrolled infants 6 months and older, so the usual floor is about 4 to 6 months. Rule out medical causes such as reflux, ear infection, or an allergy first, and keep safe sleep non-negotiable throughout: on the back, in an empty crib, on a flat surface, room-sharing without bed-sharing.⁸¹¹

It suits parents who prefer a fast, consistent approach and can tolerate a few hard nights. If the idea of not returning is too much, that is a completely reasonable reaction, and there are gentler options with evidence. The chair method keeps you in the room, the Ferber method uses timed check-ins, and bedtime fading, an under-recommended low-crying option, had real trial support in the same study that tested graduated extinction.² For the bigger picture, see when babies sleep through the night and our broader take in let us talk about sleep training.

Frequently Asked Questions