Objective: Nightmare distress, nightmare frequency and anxiety are related to suicidal risk. Ruminations are a factor maximizing the risk of suicide. Research has identified two types of ruminations: constructive ruminations and non-constructive ruminations. As per our knowledge, no study has verified the links between non-constructive ruminations and sleep disorders and their role in the development of suicidal risk. We aimed to highlight the impact of non-constructive ruminations on nightmares, anxiety and insomnia in the development of suicidal risk. Methods: A total of 429 French participants responded to an anonymous online survey using the Qualtrics (R) software. To assess variables, we used the Mini Cambridge-Exeter Repetitive Thought Scale, the Suicide Behaviors Questionnaire-Revised, the Nightmare Distress Questionnaire, the Beck Anxiety Inventory, and the Sleep Condition Indicator. Nightmare frequency was assessed by subjective evaluation through a question. We tested the possible effects of confounding variables such as age, gender, marital status and depression (Beck Depression Inventory-II). Results: Nightmare frequency was found to mediate the link between anxiety and suicidal risk (32.9%). Nightmare distress (37%) and non-constructive thoughts (48%) were also seen to mediate this link. Additionally, we found a moderating effect of insomnia on the link between non-constructive ruminations and suicidal risk (Z = 7.42, p < 0.001). Conclusion: Our results showed that the frequency of nightmares, distress and non-constructive ruminations are closely related to suicidal risk. The interoperability between these elements and insomnia has thus been newly explored. The processes related to nightmares and suicidal risk as well as the underlying cognitive processes between sleep disorders and suicidal risk have been shed light upon.
