Suicide Is a Significant Problem in the United States. Heron Et Al.1 Report That Suicide Was the 11th Leading Cause of Death in the United

93 Insomnia Symptoms, Nightmares, and Suicidal Ideation—Nadorff et al SUICIDE IS A SIGNIFICANT PROBLEM IN THE UNITED STATES. HERON ET AL.1 REPORT THAT SUICIDE WAS THE 11TH LEADING CAUSE OF DEATH IN THE UNITED States in 2006, accounting for 33,300 deaths. Although the etiology of suicidal behavior appears to be complex, steps toward understanding it can be made through the identification of suicide risk factors. Although over 90% of individuals who die by suicide have a mental disorder at the time of their death,2 the vast majority of people with mental disorders do not die by suicide. Thus, identifying risk factors beyond mental disorders may help in determining who is at the highest risk of suicidal behavior. A growing empirical literature has examined insomnia symptoms as a possible risk factor for a range of suicidal behavior, including suicidal ideation,3 suicide attempts,4 and death by suicide.5-7 Several studies have also found a relation between nightmares and suicidal behaviors.8-10 However, few studies have examined whether nightmares or insomnia symptoms are related to suicidal ideation and behaviors independent of psychiatric illness. Cukrowicz and colleagues8 examined if nightmares and insomnia symptoms were related to suicidal ideation independent of depressive symptoms in a sample of 222 college students. They found that nightmares and insomnia symptoms were both related to increased risk of suicidal ideation in college students; multiple regression revealed that nightmares, but not insomnia symptoms, were related to suicidal ideation independent of depressive symptoms.8 However, this study did not control for anxiety or Post-Traumatic Stress Disorder (PTSD) symptoms that might explain this relation. Sjöström et al.9 examined whether insomnia symptoms and nightmares were related to suicide risk independent of Diagnostic and Statistical Manual of Mental Disorders (DSM) Axis I disorders in a sample of suicide attempters.9 Their sample included 165 patients who had been admitted to a hospital following a medically serious suicide attempt. Onset insomnia, terminal insomnia, and nightmares were all significantly associated with higher scores on the Suicide Assessment Scale (SUAS). Nightmares, but not insomnia, were significantly related to high scores on the suicidality subscale of the SUAS, and remained so after controlling for DSM Axis I disorders (including major depression, other depression, psychotic disorders, alcohol/substance use disorders, anxiety disorders, and PTSD), depressive symptom intensity, and anxiety symptom intensity. Although Sjöstrom et al. demonstrated that nightmares were associated with a greater degree of suicidality among people who are suicidal, the question remains whether nightmares differentiate people who are suicidal from people who are not. Therefore, more research investigating the relation between nightmares and suicidal behavior is needed. Taken together, these initial studies indicate that nightmares appear to be a potential risk factor for suicidal behaviors, but further research is needed, particularly to determine whether the relation between nightmares and suicidal ideation is explained by PTSD symptoms. Nightmares are not only highly comorbid with PTSD, but are also a defining feature of PTSD, which has been shown to be related to suicide.11 The present study aimed to characterize the relation between insomnia symptoms, nightmares, and suicidal ideation. The study tested whether insomnia symptoms and nightmares were statistical correlates of suicidal ideation. Further, it evaluated whether insomnia symptoms and nightmares were significantly related to suicidal ideation independent of one another and independent of symptoms of psychopathology. This study sought to extend the findings of prior investigators in this area in important ways. Whereas Cukrowicz et al.8 INSOMNIA SYMPTOMS, NIGHTMARES AND SUICIDAL IDEATION IN COLLEGE STUDENTS