This article analyses secular trends in suicide and parasuicide and pr
ovides support for the hypothesis that a true increase in these phenom
ena has occurred since the early 1950s up to at least the early or mid
-1980s among the adolescent and young adult populations of Europe and
North America, particularly young men. One of the potential causal mec
hanisms for this development, increasing secular trends in and lowerin
g of age of onset for depressive disorders, is examined. Although it i
s difficult to assess whether the earlier age of onset observed for de
pressive disorders is reflected in an increase of suicide mortality at
a lower age, there is indirect evidence to suggest that this might be
the case. Studies show that lifetime parasuicide prevalence rates for
the general population do not exceed and sometimes even remain below
the rates for adolescents. Assuming that recall of past episodes remai
ns constant throughout the life span, one possible explanation for thi
s finding is an earlier age of the first-ever parasuicidal act. Since
parasuicide is an important precursor of suicide, a lowering of age fo
r first-ever parasuicides can be expected to lower the age for suicide
s and increase the overall lifetime risk.