The Relationship Between Bipolar Disorder and Multiple Sclerosis

Background: Multiple Sclerosis (MS) is a chronic, autoimmune demyelinating disease affecting approximately four hundred thousand Americans. Emotional disturbances are common and consist of mood and affective instability. Early recognition of mood disorders in MS patients is essential, as appropriate psychiatric symptom management is a major factor in morbidity and MS treatment compliance. Bipolar Spectrum Disorders (BD), in particular, have been linked to MS disease onset and symptom severity.

Objectives: We sought to determine whether BD occurs more frequently among MS patients compared to the general U.S population and whether this comorbidity is associated with worse quality of life (QOL).

Methods: We conducted a retrospective analysis of 99 consecutively recruited patients with clinically definite MS (2010 McDonald's criteria), evaluated at a single ambulatory MS center between June and December 2013. MS subtype, medication, and disease duration were abstracted from the medical record. Patients were classified as having suspected BD via a positive score on the self-administered Mood Disorder Questionnaire (MDQ) or previous psychiatric evaluation. Prevalence was measured and compared to the reported rate of positive MDQ screens in American adults. Symptom severity was assessed via the self-recorded MS quality of life (MSQOL)-54 instrument. Respective physical (MSQOL-P) and mental (MSQOL-M) health composite scores were dichotomized as <50 or ≥50 to indicate poor or good QOL, and compared among MS patients with and without suspected BD.

Results: The sample included 99 individuals with MS: mean age 48 ± 11, 73/99 (74%) women, 83/99 (84%) relapsing remitting subtype, mean MS disease duration 8.5 ± 6.4 years. 18/99 (18%) of patients screened positive for or carried a prior diagnosis of BD, relative to a reported prevalence of 3.7% in the community. MS individuals with poor MSQOL-P and MSQOL-M scores were more likely to have suspected BD (p=0.02 and p<0.001, respectively) and shorter disease duration (p=0.04 and p<0.001) than patients with good QOL. After adjustment for MS disease duration, suspected BD was independently associated with poor MSQOL-P (p=0.03, OR 3.5; 95% CI 1.1, 11.1) and MSQOL-M (p=0.001, OR 8.5; 95% CI 2.5, 29.1).

Conclusions: In our MS cohort we noted a higher than expected prevalence of suspected BD, which was independently associated with poor physical and mental health QOL. If confirmed in future studies, this knowledge may aid in the design of specific interventions targeting affective disturbances, and may help improve MS patients’ QOL.