My 18month old nephew has always been a great sleeper. He Has always gone right to bed and settled and slept through the night. About a week ago he started waking in the night and occasionally crying. In the past few nights he has been crying and screaming as soon as his mom puts him to bed. She has tried leaving him and letting him cry hoping he would soothe himself and go to sleep but last night he cried for and hour straight ans started hyperventilating so she had to go in and put him in bed with her... Why would he start behaving this way when he has always been such a great sleeper?
Who knows, he maybe reacting to something new in his daily routine, he maybe having nightmares, it could be anything or nothing at all.
In the meantime, it hardly seems worth the time and energy to resist the urge to soothe him or to reassure him. There is nothing wrong with laying down with him until he falls back to sleep.
Trust me he will outgrow his need to sleep with his mom. When was the last time you heard of a school age, junior high, high schooler or college student who still wanted to sleep with mom? They do outgrow it and often time quicker than you can imagine if you don't make a big deal of it and just out wait them.
Otherwise if you insist on this power struggle try buying a CD or two with soft soothing music like the ones with the heartbeat in the background, leaving a soft light on and making sure he has plenty of comfort toys, and something with mom's scent (blanket, shirt, etc..) to soothe himself.
M Kay Keller