Pre-Deployment
Infants | Fussy, changes in eating habits
Preschoolers | Confused, sad
School-age | Sad, angry, anxious
Adolescents | Withdrawn, deny feelings about pending separation

Deployment
Infants | No research
Preschoolers | Sad, tantrums, changes in eating habits, symptoms of separation anxiety
School-age | Increased somatic complaints, mood changes, decline in school performance
Adolescents | Angry, aloof, apathetic, acting out, loss of interest in normal activities, decline in school performance

Post-Deployment
Infants | May not recognize or be fearful of returning parent
Preschoolers | Happy and excited, but also experience anger at separation
School-age | Happy and angry, often leading to acting-out behaviors
Adolescents | Defiant, disappointed if their contributions at home are not acknowledged

Source: APA Presidential Task Force on Military Deployment Services for Youth, Families, and Service Members