Suicidal Ideation, Cognitive Dysfunction, and Sleep Disturbances in Unipolar vs. Bipolar Depression: A Cross-Sectional Comparative Study

Abstract

Background: Depressive disorders represent a major contributor to global disease burden, associated with significant disability and elevated suicide risk. While unipolar depression and bipolar depression share overlapping affective symptoms, they differ in clinical trajectory, biological underpinnings, and functional outcomes. Suicidality, cognitive impairment, and sleep disturbances are key domains influencing prognosis, relapse risk, and quality of life. Aim & objectives: To compare the prevalence and severity of suicidal ideation, cognitive impairment, and sleep disturbances in patients with unipolar and bipolar depression, and to examine correlations among these clinical variables. Materials and Methods: This cross-sectional, hospital-based study included 120 participants: 60 with unipolar depression and 60 with bipolar depression, diagnosed using ICD-10 criteria. Depressive severity was assessed using the Hamilton Depression Rating Scale (HAM-D), suicidality using the Columbia Suicide Severity Rating Scale (C-SSRS), cognitive functioning using the Montreal Cognitive Assessment (MoCA), and sleep quality using the Pittsburgh Sleep Quality Index (PSQI). Statistical analyses were performed using SPSS version 26.0, applying independent t-tests, chi-square tests, and Pearson’s correlation coefficient. Results: Mean HAM-D scores were significantly higher in the bipolar group (23.8 ± 4.6) compared with the unipolar group (20.9 ± 3.9; p < 0.01). Suicidal behavior was present in 65% of bipolar and 58% of unipolar patients, with higher mean C-SSRS scores in bipolar depression (22.4 ± 6.1 vs. 17.9 ± 5.4; p < 0.05). Cognitive impairment (MoCA < 26) was noted in 62% of bipolar and 45% of unipolar cases, with mean MoCA scores of 23.1 ± 3.2 and 25.4 ± 2.8, respectively (p < 0.01). Poor sleep quality (PSQI > 5) was observed in 80% of bipolar and 72% of unipolar patients, with higher mean PSQI scores in the bipolar group (11.2 ± 3.5 vs. 9.6 ± 3.1; p < 0.05). Depression severity demonstrated a positive correlation with suicidality (r = 0.64, p < 0.001) and sleep disturbance (r = 0.47, p < 0.01), while MoCA scores negatively correlated with PSQI (r = –0.42, p < 0.05). Conclusion: Both diagnostic groups demonstrated high levels of suicidality, cognitive impairment, and sleep disturbance; however, these impairments were significantly more pronounced in bipolar depression. The findings underscore the necessity of routine multidimensional assessment to guide individualized clinical management and relapse prevention.