Teen depression is a serious mental health condition that causes persistent feelings of sadness and loss of interest in activities. It affects how a teen thinks and behaves and can negatively impact school, family, and social functioning. Adolescent depression leads to serious problems in behavior, thinking, and of course mood at school, home, and in social situations however, depression is treatable. Teens and their parents are often educated on anxiety and the best strategies for managing symptoms. Depression, which usually starts between the ages of 15 and 30, sometimes can run in families. depression is a mood condition characterized by persistent and overwhelming feelings of. Teens that are most likely to experience depression are teens with low self-esteem, those that struggle in school as well as those who are often victims of bullying and other verbal or physical attacks from peers or even adults.