Self-Medication: The teen years are rough, and many teens who are unhappy don’t know how to find a healthy outlet for their frustration. These pent up emotions can take an emotional toll and can even lead to depression or anxiety. A 2009 study reported an estimated 70 percent of teens suffer from undiagnosed clinical depression at some point in their life. Many teens are unaware that they have an underlying mental or mood disorder that is causing them to use illegal or prescription drugs to self-medicate and cope with their symptoms.