Concurrent and Predictive Validity of the Depression Anxiety Stress Scale-21 in Multiple Sclerosis: A Cross-Sectional Study with Controlling the Confounding Factors

Background: The assessment of psychological symptoms in multiple sclerosis (MS) patients could play a key role in identifying the adverse effects of the disease. Objectives: This study aimed to assess the concurrent and predictive validity of the Depression Anxiety Stress Scale-21 (DASS-21) in patients with MS. Methods: In a cross-sectional study in 2010, 162 patients were selected by a consecutive method. Depression Anxiety Stress Scales-21 (DASS-21), the Fatigue Severity Scale (FSS), and the Short-Form Health Survey (SF-36) Questionnaire were used in this study. Data were analyzed using Pearson’s correlation coefficient and multivariate hierarchical regression analyses. Results: The findings of the present study revealed that DASS-21 subscales have a strong correlation with the constructs of fatigue and SF-36 components (r = 0.29 to -0.71; P < 0.01). In addition, each of the symptoms of depression, anxiety, and stress independently predicted a significant proportion of the variance in the scores on fatigue and eight aspects of health (P0.006) even after controlling the confounding factors. Conclusions: The present study has highlighted the concurrent and predictive validity of DASS-21 in MS. Thus, this study suggests that therapeutic interventions for reducing psychological symptoms can lead to an improvement in different dimensions of health.