Day workers suffering from a wider range of sleep problems are more likely to experience suicidality

Abstract

Both a higher suicide rate and widespread sleep problems are serious health concerns in Japan when compared with those of other countries. We investigated the relationship between suicidal ideation and sleep problems in Japanese day workers using the 3-dimensional sleep scale (3DSS), which measures three sleep elements (phase, quality, and quantity). Data from 635 Japanese day workers (461 mens and 174 womens) were included. The 3DSS was used to assess participants' sleep condition. Participants were classified into eight sleep types based on scores of phase, quality, and quantity: All Good Sleep, Owl (poor phase), Inefficient (poor quality), Short (poor quantity), Owl ? Inefficient (poor phase and quality), Owl ? Short (poor phase and quantity), Inefficient ? Short (poor quality and quantity), and All Poor Sleep. We assessed participants' suicidal ideation using question 19 of the selfrating depression scale (SDS); 119 cases (18.7 %) had ratings of 2-4 for this question and were considered to have suicidal ideation. The higher the number of sleep problems, the higher the risk of suicidal ideation compared to sleep types not indicative of problems. All Poor Sleep had the highest risk of the eight sleep types. Individuals with Owl ? Short, Inefficient ? Short, or All Poor Sleep had a significant risk of suicidal ideation even after adjusting for hopelessness and nightmares. Our findings suggested that sleep problems assessed by the 3DSS were related to suicidal ideation. Analysis of various aspects of sleep could be helpful for suicide prevention.

The relationship of sleep complaints risk factors with sleep phase, quality, and quantity in Japanese workers

“…This suggests that it is necessary to assess sleep phase, quality, and quantity separately to clarify the causes of sleep complaints and respond appropriately. Compared to a previous study [ 20 ], the prevalence of poor sleep phase in this study was lower while that of poor sleep quality or quantity were similar. Specifically, the previous study reported that the prevalence of poor sleep phase was about 44%, whereas in this study, it was 37%.…”

“…In the past, we established that sleep comprises three measurable elements—phase, quality, and quantity—which we then integrated into an original scale called the 3-Dimensional Sleep Scale (3DSS) [ 19 , 20 ]. In our current 24-h society, people often exhibit problems in their sleep phase (e.g., regularity and chronotype), as well as in their sleep quality (e.g., sleep efficiency and satisfaction) and quantity (e.g., sleep duration and fullness).…”

Suicidality in sleep disorders: prevalence, impact, and management strategies

“…At this point, we can make the argument that sleep disturbances may be a marker of distress and suicide risk 127 and that multiple concurrent sleep problems may confer greater risk for suicide than single sleep problems. 66 , 141 Mechanisms explaining the relation between sleep disorders and suicide remain needed, including more research rigorously examining the efficacy of sleep-disorder treatments on assuaging suicide risk. Research examining the impact of sleep disorders on suicide risk has been circumscribed to a few sleep-disorder symptoms, with much less known about the prevalence and management of suicide risk across all sleep disorders.…”

“…Research focusing on chronotypes have shown associations between an “eveningness” preference and suicide-related thoughts 141 – 144 and behaviors (ie, lifetime and violent suicide attempts). 145 , 146 An eveningness preference has also been associated with elevated scores on measures of depressive symptoms, hopelessness, and defeat.…”

“… 147 Additionally, an eveningness preference coupled with short sleep duration was associated with greater odds of suicide ideation when adjusting for demographics, hopelessness, and past-month sleep problems due to bad dreams. 141 Although associations have been shown between eveningness and suicide risk (current and lifetime), 110 , 146 some studies have shown that eveningness was not associated with current (when adjusting for depressive symptoms) 148 or lifetime suicide risk. 147 …”