Screening for depression in myasthenia gravis

Introduction: There are conflicting reports of depression prevalence in myasthenia gravis (MG). The influence of somatic symptoms on screening assessments is not apparent. We investigated the frequency of somatic and non-somatic symptoms of depression in MG. We also explored the relationship between depression and MG using disease severity and quality of life measures. Methods: Three cohorts of participants (MG, healthy and disease controls) were prospectively assessed with the Beck Depression Inventory 2 (BDI-II) and BDI-Primary Care (BDI-PC) surveys, modified Rankin Scale, MGFA classification, MG-MMT, MG-ADL and MG-QOL15. Results: A total of 31 MG, 29 disease controls, and 30 healthy controls were enrolled. Depression frequency indicated by BDI-II in MG 48% (15/31) and disease control 31% (9/29) was not significantly different [p=0.17]. However, we found a significantly higher frequency than healthy controls 10% (3/30) [p=0.001]. In contrast, depression frequency indicated by BDI-PC was similar in the MG 29% (9/31) and disease controls MG, 24% (7/29)[p=0.77] as well as the healthy controls 10% (3/30) [p=0.08]. Using the BDI-II scale, participants with MG who were depressed had higher scores on MG-MMT, MG-ADL, and MG-QOL15 than those who were not depressed. The difference in MG-ADL and MG-QOL15 scores remained significant using the BDI-PC score. Discussion: These findings suggest depression screening assessments that include physical symptoms overestimate depression in MG and chronic autoimmune neuromuscular disorders. A higher frequency of self-reported depression is associated with increasing disease severity and low quality of life.