Objective: The current study was set out to investigate differences between patients with multiple sclerosis (MS) and healthy controls in sleep quality, worry and dissociative experiences. We also explored the potential correlates of functional impairment in this group.

Method: Eighty-eight patients with MS and a hundred and thirty-nine healthy adults participated in the study. The mean age was 30.96 (SD ± 8.88). The Expanded Disability Status Scale (EDSS), Dissociative Experiences Scale (DES), Penn State Worry Questionnaire (PSWQ), and Pittsburgh Sleep Quality Index (PSQI) were completed by clinical and nonclinical subjects. Binary logistic and multiple regression analyses were performed.

Results: 55.7% of MS patients were identified as poor sleepers. However, total scores on the PSQI did not differ significantly between clinical and nonclinical subjects. Logistic regression analysis showed that patients with MS reported significantly lower levels of habitual sleep efficiency than healthy controls. Interestingly, healthy adults reported greater scores on pathological worry than patients with MS. Patients with MS and healthy adults did not differ on the DES scores. Duration of the illness and worrisome thoughts were significant antecedents of the functional impairment occurring during the course of the illness.

Conclusion: Patients with MS had poor habitual sleep efficiency, which may be a significant risk factor for management and improvement of the illness. Pathological worry seems to be associated with disability status. Cognitive behavioral interventions including sleep-informed instructions should be integrated into clinical practices to enhance positive outcomes during the course of the treatment in this group.