Children younger than age 18 can experience one of two types of mood disorders: major depressive disorder (MDD) and bipolar disorder. Treatment For bipolar disorder, the first treatment response is typically mood stabilizers or antipsychotic medications. Childrenwith MDD are usually treated with antidepressants, psychotherapy or both. Signs and symptoms Major Depressive Disorder (MDD): Feelings of sadness, worthlessness and guilt; disinterest in normal activities; changes in sleep patterns and appetite; fatigue; suicidal thoughts/actions; and impaired cognitive functioning. Depressed children typically withdraw from friends, family members and school.