The role of psychological factors in the relationship between sleep disturbance and suicidality in bipolar disorders and general population

Abstract

This current involves two studies which aimed at investigating the relationships among sleep disturbance, suicidality, and psychological factors in patients with bipolar disorders and in a community-based sample of young adults. In Study One, 90 Chinese adults aged between 18 and 65 with bipolar disorders and 90 healthy normal controls matched on age, gender and race were recruited. Sleep disturbances were assessed by Insomnia Severity Index (ISI), Nightmare Distress Questionnaire (NDQ), Nightmare Frequency Questionnaire (NFQ), the reduced version of Morningness-Eveningness Questionnaire (rMEQ), and sleep diary. Suicidal ideation was measured by Beck's Scale for Suicide Ideation (BSS). Regarding the two psychological factors namely rumination and impulsivity, rumination was measured by Rumination Response Scale (RRS). Impulsivity was measured by Barratt Impulsiveness Scale-11 (BIS-11), Iowa Gambling Task (IGT) and Cued Go/no-go Task. In Study Two, 210 Chinese young adults aged 18 to 25 without significant depression and anxiety symptoms, as defined by the cutoff in the Depression Subscale and the Anxiety Subscale of Depression Anxiety Stress Scale (DASS-21), were recruited. Sleep disturbances were assessed by ISI, NDQ, and rMEQ. Suicidality was measured by Depressive Symptom Inventory - Suicide Subscale (DSI-SS). Three psychological factors namely rumination, impulsivity and hopelessness were measured by Rumination Response Scale (RRS), Barratt Impulsiveness Scale-11 (BIS-11) and Beck Hopelessness Scale (BHS) respectively. The research findings identified sleep disturbances (insomnia severity, nightmare distress, preference towards eveningness) and psychological risk factors (rumination and impulsivity) as risk factors for suicidality independent of the diagnosis of bipolar disorders. It also provided the first piece of evidence in Chinese college population that hopelessness mediated the relationship between insomnia severity and suicidality. This finding might indicate the needs of assessing sleep disturbance and cognitive processes for early detection of young adults with high suicidal risk. It might also identify hopelessness as a treatment focus to be targeted in suicide prevention and management in high-risk young adults, particularly those with insomnia problems.