Dark Tetrad Traits and Suicidal Ideation in Psychiatric Patients: The Role of Depression, Anxiety, and Stress

This study examined direct and indirect associations of Machiavellianism, narcissism, psychopathy, and sadism with suicidal ideation through depression, anxiety, and stress in psychiatric patients. A cross-sectional sample of 210 patients completed the Short Dark Tetrad (SD4), Depression Anxiety Stress Scales-21 (DASS-21), and Suicidal Ideation Attributes Scale (SIDAS). Regression paths were estimated using robust maximum likelihood, whereas indirect effects were evaluated using 10,000 bootstrap resamples. Because 92 participants (43.8%) had SIDAS = 0, two-part sensitivity analyses separated the occurrence from the severity of suicidal ideation; additional analyses excluded the two smallest diagnostic groups. Depression, stress, and anxiety correlated with SIDAS (r = 0.560, 0.509, and 0.466, respectively). The sadism–stress–SIDAS indirect effect was significant in the primary model (B = 0.147; 95% bootstrap CI [0.037, 0.291]), after covariate adjustment (B = 0.126; 95% bootstrap CI [0.016, 0.266]), and after excluding psychotic and bipolar groups (B = 0.115; 95% CI [0.006, 0.259]). In two-part analyses, depression was associated with SIDAS occurrence, whereas stress and sadism were associated with severity among participants with SIDAS > 0. The findings support a stress-related indirect association between sadism and suicidal ideation, but causal interpretation is not warranted.