The varied problems of adolescent persons are direct expressions of the personality changes of this period and the emotions that are associated with these. The stimulus that evokes these changes is the need to cope with increased sexual drive. To do this the adolescent must change from a childhood emotional position that depends on parents for direction and must seek and achieve a new sense of personal identity which is self-dependent and which is in harmony with a conscience which also must be remodeled during this period. The struggle to achieve this personality change produces the emotional reactions, many psychological and medical problems, and the behavior characteristic of teen-agers.
Delano JG. Psychiatric Implications of the Teen-Agers' Problems. JAMA. 1963;184(7):539-543. doi:10.1001/jama.1963.03700200061011