Babies can show signs of separation anxiety as early as 6 or 7 months of age, however, the typical age is between 12 to 18 months.
It is natural and common for a child to become tearful or have a tantrum when a parent tries to say good-bye to leave for work or run an errand, and turn the caregiving temporarily over to someone else.
However, if your childs' anxieties are continuous and seem unreasonable, it is possible that he/she has separation anxiety disorder.
Although symptoms of separation anxiety disorder can be unsettling, having a few methods on hand to deal with the anxiety can help create a calmer setting for your child.
Children that have separation anxiety disorder frequently feel uneasy or scared about separation, and can show the following symptoms:

• concern that something awful will happen such as their parent getting ill or hurt
• worry that once separated, they may get lost or kidnapped
• nightmares about their fears of separation
• refuse to attend school
• unwillingness to go to sleep, due to worry of being alone or having a nightmare
• complain of a headache or stomachache
• following parent around the house in a clinging fashion

In trying to work through symptoms of separation anxiety disorder, the following five tips to help your child feel safe and secure, as well as to encourage independence include: 1) maintain a consistent and predictable schedule - discuss any changes ahead of time with your child 2) show calmness yourself and your child will be more likely to remain relaxed as well during a separation 3) let your child know that while you appreciate his/her feelings, there are rules and limits that need to be followed in the household 4) provide your child a choice in an activity or communication with you - this gives him/her some control and will bring about a greater sense of comfort and safety 5) give positive reinforcement by celebrating your childs' achievements - a good report card, going to bed without a hassle, remembering to feed the dog In learning more about separation anxiety disorder, you will be in a better position to sympathize with your childs' concerns.
Listening to his/her feelings and talking about them will help your child learn to survive future separations more easily.