Depression is something that affects many preschool age children, maybe even one you know. Sometimes kids as young as 3-years-old suffer from depression and the condition can often be misdiagnosed.

Depression affects approximately four percent of preschoolers in the United States right now.

Symptoms include a child who refuses to eat, is having difficulty going to sleep, or is waking up during the night.

"Parents should look for kids who are persistently sad and irritable, usually for more than two hours in a day, more days than not in a week," said Dr. Joan Luby, Child Psychiatry of Washington University in St. Louis.

Doctors say you should seek medical advice if that behavior lasts longer that 7-to-9 months or more frequently.

Because antidepressant medication is not recommended for treating children under the age of six, the most common treatment is therapy.

Your child could be predisposed to depression. The Canadian Mental Health Association says if one parent suffers from depression, their child will have a 25 percent chance of also experiencing depression. That percentage triples to 75 percent when both child's parents have the disorder. The percentage of children with depression jumps from one or two-percent in preschool to eight-percent by the time children reach the adolescent years, ages 12 to 18.

Bottom line, doctors say parents need to take their children's emotional complaints or symptoms seriously.