Toddler expert, Ann Richardson, responds:
It sounds like your little one may be suffering from night terrors. Night terrors are not bad dreams, and actually occur when a child is in deep sleep. They are different to nightmares in that the child wakes up (usually screaming), and is utterly inconsolable.
There is not much you can do for your child at this time, other than holding her tightly and reassuring her that you are there for her. You may have to ensure she is fully awake before you attempt to calm her down. Stay calm, sing a reassuring lullaby and sit it out. Most night terrors subside after a few minutes, but may occur more than once a night.
Research has shown that night terrors are common in children with abnormal sleep schedules, so try to encourage a daytime nap, move her bedtime earlier and avoid excessive stimulation during the day, particularly before bedtime.
It is also important to bear in mind that 18 months of age is a peak time for separation anxiety, so try to spend some extra time with her during this phase.
Nightmares are different to night terrors in that you can easily comfort your child, and often they don’t even wake upfully. They occur during the light sleep cycle of sleep, and are usually a passing phase. They have no lasting effect on your child nor are they associated with any specific emotional problems.