In this study, that follows another one, where the normal characteristics of adolescence that may influence suicidal behavior were focalised, a critical review of the psycho-social elements involved in the matter is done; attention is also given to the clinical picture. The family influences are very important and frequently we find antecedents of suicidal behavior in parents or in near relatives. The homes are usually unhappy with a father absent or "feeble". It is not rare the presence of a dominant-rejecting mother. The home is poor in love expressions, and the intra and extra family reactions tend to lead to the youth social isolation. With the changes that normally happens in adolescence, the repressed aggressive impulses increase and tend for discharge at this phase, but usually the youth turns them against himself. The emergent genital sexuality is also perceived as threatening by the parents. Though lacking more detailed studies, it seems that families of suicidal adolescents are very similar to the families of depressive ones. In females, cultural influences such as greater tolerance to suicidal attempts behavior, perhaps explain the higher incidence of this behavior. Men usually use violent methods for consumating the suicide, and often their mental status is more severe than in females. The precipitant factors vary a lot but they usually give evidence of a conflictive situation. It is suspected that often the patient unconsciously puts himself in the difficult situation. The influence of mental illness in the suicidal behavior of adolescents is complicated by several classificatory systems and the possibility of considering abnormal aspects that normally occur during adolescence. In the clinical picture is important to consider the patient report about his suicidal thoughts. The evaluation of the defences, the intensity of the conflict and the suicidal ideas involved, will determine our conduct. An important feature is that, in adolescents, depressive symptoms usually occur as "equivalents". The prognostic is worse when it is impossible to modify family relationships and when social life continues unpoverished. In 40% of the cases a new suicide attempt is done, and the risk is greater during the year that follows the first attempt. Prevention may be done by trying to understand and discuss adolescents problems with them in their peer groups. Public campaigns and courses with moral appeals should be avoided because they increase feelings of guilt. Special attention has to be given in each case to social and family situations. An early diagnosis by pediatricians, clinicians, teachers and law authorities is very important. To do this work they need to have instruction about the adolescence developments.