Suicidal ideation and associated factors in early and late onset late life depression

Early-onset depression (EOD) and late-onset depression (LOD), as subtypes of late-life depression (LLD), exhibit distinct clinical and biological characteristics. Patients with LLD are at an increased risk of developing suicidal behavior in the presence of suicidal ideation. This study aims to investigate suicidal ideation and its associated factors in patients with EOD and LOD. In this study, data were obtained from individuals aged 60 and over who were diagnosed with major depressive disorder (MDD) at a state hospital. Eligible participants completed the Beck Depression Inventory (BDI), the Beck Scale for Suicidal Ideation (BSSI), and the Patient Health Questionnaire-15 (PHQ-15). The study sample consisted of 100 participants, including 51 with EOD and 49 with LOD. The BSSI score was significantly higher in the EOD group ( p = .038). The number of previous depressive episodes was associated with the BSSI scores (β = 0.282, p = .022). The regression model explained 12.8% of the variance in BSSI scores (R² = 0.128, adjusted R² = 0.091, f² = 0.147). However, no significant association was found between depression severity (BDI) and suicidal ideation (β = 0.145, 95% CI [-0.054, 0.387], p = .138), although this null finding should be interpreted with caution given the limited statistical power (post-hoc power = 0.52). Additionally, the age at first onset of depression showed a significant negative correlation with BSSI ( r = -.211, p = .035). Post-hoc power analysis revealed that the achieved power for detecting the significant correlation between number of previous depressive episodes and BSSI was 0.89. Supplementary analysis comparing patients with and without a history of recurrent depression revealed significantly higher BSSI scores in the recurrent group ( p = .004), further supporting that recurrence status, rather than age of onset per se, may be the primary driver of suicidal ideation in this sample. This study indicates that suicidal ideation is higher in patients with EOD, and that suicidal ideation is associated not with the severity of depression or the level of somatic symptoms, but rather with the number of previous depressions. However, given the substantial confounding between EOD status and recurrence history in our sample, the association between early onset and suicidal ideation should be interpreted with caution. The modest sample size limits the ability to detect small-to-moderate effects, and the non-significant BDI finding should be interpreted with caution.