The study is an analysis of statistics only and indicates nothing regarding the potential cause of the documented trend. The more important points of the study were not quoted, of course:
Not that adoption causes suicide, only that identifying this trend may help at-risk teens to get help sooner.
And:
Although the mechanism underlying the association remains unclear, recognizing the adoptive status may help health care providers to identify youths who are at risk and to intervene before a suicide attempt occurs.
Not that adoption causes suicide, only that identifying this trend may help at-risk teens to get help sooner.
And:
It is important to note, however, that the great majority of adopted youths do not attempt suicide and that adopted and nonadopted youths in this study did not differ in other aspects of emotional and behavioral health.