Some children are noticed to experience extreme fear and discomfort when they are separated from their parents. They may show a persistent worry that the parent will leave them and not return. This fear may even lead to refusal to go to school. They may cry and throw tantrums if they understand they are being separated from their parents. At any time during the day and while going to sleep the child may refuse to be left alone. The child may even have physical symptoms such as nausea, headache, vomiting, when he or she is separated from the parent.