Role of Depression and Anxiety As Mediators Between Insomnia Symptoms and Suicide Ideation in Patients With Adjustment Disorder

Objective: The aim of this study was to evaluate whether insomnia can independently affect suicide ideation or whether insomnia affect suicide ideation by mediating depression or anxiety in adjustment disorder (AD). Methods: Electronic medical records were retrospectively reviewed for 65 patients with diagnosed AD visited an outpatient clinic between January 2018 and December 2020. Measurements include the Insomnia Severity Index (ISI), Beck Depression Inventory-II (BDI-II), State-Trait Anxiety Inventory (STAI) and Minnesota Multiphasic Personality Inventory-2 (MMPI-2). Statistical analyses were performed to assess relationship between insomnia and suicide ideation in AD and the mediating role of depression or anxiety in this association. Results: During 3 years of study period, of the AD patients, 37 (57%) were male and 28 (43%) were female. Among them, 45 (69.2%) and 23 (35.4%) had clinically significant symptoms of insomnia (ISI ≥15) and suicide ideation (MMPI scale score ≥70), respectively. In a mediation model using depression and anxiety as mediating variable, there were significant effects of insomnia on depression (t=5.55, p<0.001) and anxiety (t=6.21, p<0.001) and of depression (t=5.70, p<0.001) and anxiety (t=3.54, p<0.001) on suicide ideation. Total effect of insomnia on suicide ideation was statistically insignificant, suggesting complete mediation. Conclusion: A significant association with suicide ideation was observed in the case of insomnia accompanied by depression and anxiety. Therefore, in patients with AD who complain of insomnia, symptoms of depression and anxiety should be evaluated by clinicians with active intervention for suicide ideation.