This booklet begins with a poem written by an adolescent undergoing psychotherapy for depression, then goes on to describe what depression is and to examine sex and age differences related to depression. The difference between clinical depression and feeling blue is explained. Various therapies used in the treatment of depression are identified. The next section looks specifically at the changes that occur during adolescence, including physical, intellectual, and psychosocial changes. The next two sections focus on identity formation and implications for health professional of identity formation research. Manifestations of adolescent depression are listed and the association between adolescent depression and the adolescent's relationships with parents and peers is described. The next three sections examine depression and low self-esteem, adolescent loneliness, and suicide and the adolescent, respectively. Depression, suicide attempts, and suicide completion are compared for adolescents, young adults, and adults. The booklet concludes with a section on youth suicide prevention. (NB)