I know I may ruffle some feathers here, but I feel that I need to make a few things clear.
First of all, and this one if my personal opinion; crying it out is not to be used before a baby is about 6 months old and can sleep through the night without feedings. If you are not feeding your baby in the night when he/she needs to nurse or have a bottle, you are depriving your baby of his or her needs. Babies over 6 months do not require nighttime feedings, but before that age they do. It doesn't matter if you are adding cereal to their bottles (big no-no in my books anyway) or feeding them a snack before bed and they are 5 months old. Their tiny tummies can't hold enough food or milk to last them the night.
Second point; No baby, especially a small one should be left to cry for hours on end without being soothed, calmed or reassured that you are there for them. Babies need their parents and to feel secure. If you just drop your baby off in their crib and go to bed for the night allowing them to scream and cry for hours until they can "soothe themselves" there is no doubt that this can cause mental harm to them. This is a huge mistake that a lot of people I know make. They don't read any information and just assume that crying it out means to let them cry until they fall asleep....and we all know what assume spells- ASS out of u and me! Crying it out involves going in and soothing your child in increasing time increments. So, every 5, 10, 15... minutes you need to check on them, lay them back down, rub their head, whatever calms them. It is not a quick- fix method. It takes effort and time.
Basically what I'm saying is that people need to educate themselves before they even try CIO. There are guidelines which should be followed for a reason. Babies still require their basic needs to be met (such as diaper changes and reassurance if needed) at any age . If parents don't follow these guidelines, these babies could result in emotionally damaged human beings.
It really scares me to think that to some parents their sleep is more important than meeting the needs of their children. Don't get me wrong, I have two children of my own and have felt sleep deprivation first hand but when you make that decision to become a parent, you also make the decision to put your child first.
Keep in mind that this is only my opinion, since it is my blog after all but I had to get this off my chest. Phew!