Yes. Multiple studies have shown that sleep training is both safe and effective, without any studies showing evidence of harm. The best long-term study followed 326 children for the first six years of life. The authors reported that children who had sleep trained via any method in infancy slept better at 2 years of age than children who were not sleep trained, and their mothers were less likely to be depressed. Several years later, the researchers looked at these children again and noted that there was no evidence of emotional or behavioral problems in children who had been sleep trained versus those who had not. As part of this follow-up, the researchers measured the children’s levels of the stress hormone cortisol, which is frequently cited by opponents of sleep training as the mechanism by which crying affects developing brains. The researchers did not find any evidence of differing levels of cortisol secretion between children who had been sleep trained and those who had not.
"I have two kids. The first one was never left to cry it out – we rocked, sung, walked, drove her to sleep until she was old enough to be read a story. Then, with baby number two, I decided to try CIO and after one night, it worked. At 12 months, she goes to sleep at night by herself and never cries. It was the best thing I did. My husband was against it, but he wasn't the one up four or five times every night for nine months straight! Now our household is very happy and everybody sleeps well."
“There are many variations to any sleep training method. For example, you can do a cross between The Chair Method and PUPD with great success and fewer tears! There are also ways of breaking each method into smaller baby steps, which we recommend very often in our Personalized Sleep Plans®. Find what feels tolerable (because, frankly, no one ‘likes’ to sleep train), more comfortable for you, and what seems the gentlest, yet effective, on your baby, depending on his or her temperament and personality.”
"As you modify your baby's sleep behavior, you are going to have to give up middle-of-the-night crutches, known as negative associations, that may get her back to sleep in the short run but won't prevent her from popping up again in an hour. She may resist the change. The behavior may even get worse before it gets better as she adjusts to new routines, to new positive associations."
Sleep training is a loaded phrase, and one that is often used synonymously with letting your baby self-soothe, or “cry it out,” but that’s not the whole picture, says Alanna McGinn, a certified sleep consultant and the founder of Good Night Sleep Site. “It’s more about being able to teach your baby that they are capable of falling asleep independently,” she says. You want your baby to be able to nod off on their own—ideally without nursing, rocking or using a pacifier—because whatever tools they use to fall asleep at bedtime are the same things they’re going to wake up looking for during the night. Yes, this can feel unloving and even downright cruel. You’ll find experts on both sides of the issue: Breastfeeding advocates say it’s normal for babies of all ages to wake up multiple times to nurse, and even the sleep coaches interviewed for this article disagree with how much crying and distress are acceptable.