LAUSR

While nightmares are well known to be associated with greater sleep disturbance and psychopathology relative to insomnia, this has primarily been observed in experimental samples and not well-studied in outpatient clinical samples. Several theories for the etiology and maintenance of nightmares have identified the roles of both hyperarousal and emotion dysregulation in explaining the association of nightmares to adverse psychiatric outcomes. Given that insomnia is also associated with similar predisposing and perpetuating factors such as greater trait arousability and sleep reactivity, it is important to understand how these factors compare between nightmares and insomnia. A total of 445 patients (45.6±18.4 years old, 66.5% female, 13.0% minority) with diagnoses of nightmare disorder (n=32), insomnia disorder (n=274) and any other sleep disorder (n=139) were evaluated at the Behavioral Sleep Medicine (BSM) program of Penn State Health Sleep Research & Treatment Center. To measure symptoms of depression, anxiety, stress, hyperarousal, sleep reactivity, and dysfunctional beliefs about sleep, all patients completed the Depression Anxiety Stress Scale (DASS), Arousal Predisposition Scale (APS), Ford Insomnia Response to Stress Test (FIRST), Pre-sleep Arousal Scale, and Dysfunctional Beliefs and Attitudes about Sleep (DBAS), respectively. Analysis of variance (ANOVA) examined between-group differences in patient-reported outcomes. There were no significant between-group differences on sleep reactivity, pre-sleep cognitive arousal, dysfunctional beliefs and attitudes about sleep or depression scores (all ps>0.12). However, patients with nightmare disorder showed greater arousability, in both trait anxiety and emotional reactivity, pre-sleep somatic symptoms, anxiety and perceived stress than patients with insomnia disorder or with any other sleep disorder (all ps< 0.05). While patients with nightmare disorder share predisposing and perpetuating factors common to patients with insomnia disorder, they do present with more severe forms of cognitive-emotional arousability, trait-anxiety, and somatic symptoms of anxiety that impact nighttime sleep. These data suggest that clinical evaluations for sleep disruption should include a thorough gathering of history to include the onset, course, and perpetuating factors. Cognitive-behavioral therapies for nightmares and insomnia should be tailored to target these specific factors in order to prevent relapses.