Teenage depression. A bigger concern is thar teenagers self medicate depression via use of marihuana and this is rising. Cannabis is one of the most commonly used illicit drugs, and despite the widely held belief that it is a safe drug, its long-term use has potentially harmful consequences including the development of psychosis. The use of alcohol and drugs is highly correlated with mood disorders in teenagers.
Depression. As in adults depression in teenagers can be situational, due to an underlying genetic predisposition, or drug induced. The genetic form of "unipolar" or bipolar depression can be hard to diagnose in adolescents. It used to be thought that bipolar disorder started as an adult, but we now know it starts much earlier.
All too common. Pathologists like me see too much teen suicide, and this question gets asked after almost each one. Thoughts of suicide, hopelessness, or giving up are never a normal part of growing up. Some teens are trapped in impossible home situations, learn social skills slowly, and most still lack marketable skills, making it even more important to support and guide rather than scream at them.