Reduced Slow-Wave Sleep and Sleep-Disordered Breathing Are Linked to Suicidal Ideation in Major Depressive Disorder

Suicidal ideation (SI) is common in major depressive disorder (MDD) and has been linked to sleep disturbances. However, the relative contributions of subjective sleep quality and objective sleep architecture to SI remain unclear.

A total of 103 inpatients with MDD underwent polysomnography (PSG) and completed the Pittsburgh Sleep Quality Index (PSQI). Based on HAMD-17 item 3 scores, participants were classified into SI (n = 49) and non-SI (N-SI, n = 54) groups. Clinical characteristics, subjective sleep quality, and PSG-derived sleep parameters were compared between groups. Binary logistic regression was performed to identify independent predictors of SI.

Compared with the N-SI group, patients with SI had longer illness duration, more depressive episodes, higher depressive severity, and poorer subjective sleep quality. PSG analyses revealed that SI patients showed significantly lower N3% and higher apnea-hypopnea index (AHI). Logistic regression indicated that PSQI score, N3%, and AHI were independent predictors of SI. A combined model incorporating these three factors demonstrated excellent discriminative ability (AUC = 0.924) for identifying SI.

Both subjective sleep disturbance and objective sleep abnormalities, specifically reduced slow-wave sleep and elevated AHI, are strongly associated with SI in MDD. Integrating subjective and objective sleep assessments may enhance suicide risk detection and guide targeted interventions for prevention.