Pseudobulbar Affect in Patients with Multiple Sclerosis: A Systematic Review

Multiple sclerosis (MS) is associated with a high prevalence of emotional disorders affecting the health-related quality of life of patients and their families. Pseudobulbar affect (PBA), also referred to as pathological laughing and crying, is an under-recognized and under-treated co-morbidity. We conducted a systematic literature review of 16 studies to determine the prevalence and clinical characteristics of PBA in patients with MS of all ages. Based on conservative figures available from 8/16 studies, the prevalence of PBA in the context of MS was found to range between 2% and 10% (median 10%), with higher percentages in the female population. Possible reasons for the observed variability in the prevalence data include heterogeneity of the diagnostic methodologies and common presence of confounding factors, such as co-morbid affective disorders. The clinical presentation was found to be comparable to that of PBA in the context of other neurological disorders, as it reflected the location of underlying lesions (especially in the brainstem) rather than the associated pathology. Clinicians should be prompted to consider PBA in the differential diagnosis of emotional disorders in the context of MS by using both clinical criteria and psychometric instruments. Further studies should be conducted to develop standardized diagnostic protocols and to optimize therapeutic approaches for the clinical management of this patient population.