What symtoms would a preschooler have if he had depression ?

Several symptoms: Internalizing symptoms such as sadness, anhedonia (lack of fun), shyness & physical complaints, & externalizing symptoms such as anger can be seen in depressed kids as young as 3 (see luby j. Clinical child & adolescent psych, 2009; & luby, preschool depression: importance of identification of depression early in development, trends in psych science, 2010). Start w/ pediatrician if concerned.