The objective of this study was to determine whether, and to what extent, those who reported suicidal ideation and (or) attempts in the previous year, without meeting the criteria for major depressive episode (MDE), might still have experienced subthreshold depression.

Data from the Canadian Community Health Survey: Mental Health and Well-Being (CCHS 1.2) were examined to estimate and compare the prevalence of depressed mood, a core symptom of MDE and subthreshold depression, within the previous month for the following four population groups: MDE within the previous month [D(1 month)], MDE within the previous year but not the previous month [D(1 year)], suicidality without MDE within the previous year (D_S+), and no MDE or suicidality within the previous year (D_S_).

As expected, the D(1 month) group showed the highest prevalence of depressed mood in the previous month.  However, the D_S+ group had a significantly higher prevalence of depressed mood than the D_S_group and only a slightly lower level than that of the D(1 year) group.

A fraction of those who reported suicidality in the previous year met the criteria for MDE during that time; however, subthreshold depression might be common in the suicidal population.  Future epidemiologic research in the areas of suicidality and depression will benefit from a comprehensive assessment of subthreshold depression.