Role of depression severity and impulsivity in the relationship between hopelessness and suicidal ideation in patients with major depressive disorder

•To construct a pathway model of suicidal ideation.•Depression severity has a mediation between hopelessness and suicidal ideation and this mechanism was contingent on the levels of impulsivity.•To highlight the importance of impulsivity assessment and alleviation of depressive symptoms to prevent suicidality in MDD patients.

BackgroundHopelessness, depression and impulsivity all contribute to the development of suicidal ideation in patients with major depressive disorder, but the pathway of these factors to suicidal ideation is not clear. This study examined the meditating effect of depression severity on the relationship between hopelessness and suicidal ideation and explored how this mediating effect was moderated by impulsivity.MethodsA total of 162 patients with major depressive disorder (MDD) completed a structured clinical diagnostic interview and a battery of scales assessing depression severity, hopelessness, suicidal ideation, and impulsivity. Regression analyses with bootstrapping methods were used to examine the mediating and moderating effects of various risk factors.ResultsMediation analysis revealed a significant indirect effect of hopelessness on suicidal ideation, and the effect was fully mediated through depression severity. On moderation analysis, the moderating effects of the relationship between depression severity and suicidal ideation were significant in both the medium and high impulsivity groups.LimitationsThe present study was limited by the assessment of trait impulsivity and observer-rated depression severity, which might not fully reflect momentary impulsivity and feeling of depression when suicidal ideation occurs.ConclusionDepression severity plays a mediator role in the relationship between hopelessness and suicidal ideation and this mechanism is contingent on the levels of impulsivity. MDD patients with higher impulsivity appear to be more likely to have suicidal ideations even when they are less depressed. These findings highlight the importance of impulsivity assessment and alleviation of depressive symptoms to prevent suicidality in patients with MDD.