The relationship between repetitive negative thinking, sleep disturbance, and subjective fatigue in women with Generalized Anxiety Disorder

Objectives Fatigue is a prominent symptom of Generalized Anxiety Disorder (GAD). However, the pathways contributing to elevated fatigue in GAD are poorly understood. Sleep disturbance, also prominent in GAD, only partially explains elevated fatigue in GAD. Repetitive negative thinking (RNT) is a cognitive feature of both GAD and sleep disturbance, and RNT has recently also been associated with elevated fatigue. Therefore, this study assessed whether elevated fatigue in GAD is accounted for by a combination of sleep quality and RNT. Design Between-group, correlational design in 64 primarily university-educated women with and without a GAD diagnosis. Methods Women completed self-report questionnaires assessing RNT experienced in the past few days, previous night's sleep quality, and current physical and mental fatigue. Hierarchical linear regressions were conducted to assess whether the relationship between GAD status and fatigue is accounted for by RNT and sleep quality. Results Women with GAD reported lower sleep quality, and higher RNT and physical and mental fatigue, compared to women without GAD. Sleep quality partly accounted for group differences in both types of fatigue (beta's > -0.4), whereas RNT fully accounted for group differences in both types of fatigue (beta's > 0.29). The relationship between RNT and both types of fatigue was fully accounted for by sleep quality (beta's > -0.39). Conclusions These findings indicate that heightened RNT amongst women with GAD may be associated with elevated physical and mental fatigue via its detrimental effects on sleep quality. Interventions that reduce RNT may help to alleviate fatigue symptoms in women with GAD. Practitioner points Women with Generalized Anxiety Disorder (GAD) have elevated fatigue and repetitive negative thinking (RNT), and poorer self-reported sleep quality, relative to women without GAD. Whereas sleep quality only partially accounts for elevated fatigue in GAD, RNT fully accounts for elevated fatigue, and the relationship between RNT and fatigue is fully accounted for by sleep quality. These findings provide novel evidence that women with GAD may have elevated fatigue because of the detrimental effects of RNT on sleep. These findings suggest that targeting RNT in treatment for GAD may help to reduce fatigue in GAD, by improving sleep quality.