The systemic review and meta-analysis, believe the researchers, is the first of its kind to characterize the prevalence of depression among these patients.
More than one-third of patients with myasthenia gravis (MG) experience anxiety and depression, say findings of a new study published in Brain and Behavior, which also indicated that the impact of these psychiatric disorders in these patients is higher than in other patients with autoimmune diseases.
The systemic review and meta-analysis, believe the researchers, is the first of its kind to characterize the prevalence of depression among these patients. While research has been dedicated to identifying the prevalence of depression and anxiety in these patients, there have been mixed results and an absence of a systematic review or meta-analysis.
“MG mainly affects acetylcholine receptors and disturbs their mechanism. In most MG cases, the first symptoms are the weakness of extraocular muscles and ocular misalignment, which is considered as ocular MG,” wrote the researchers. “Within 3 years, in around 90% of cases, ocular MG develops to generalized MG, which is defined by symptoms of weakness and fatigue in skeletal muscles and its effects on swallowing, chewing, breathing, and talking of MG patients. Disabilities resulting from MG often affect patients’ quality of life and interfere with their daily routine and activity. Additionally, instability of MG symptoms, prolonged illness, and treatment with steroids can cause psychiatric symptoms in MG patients.”
Data were compiled from 38 studies comprising more than 4000 patients, which showed a pooled prevalence of depression of 36% and a pooled prevalence of anxiety of 33%, both higher than previously identified rates in other autoimmune diseases like multiple sclerosis and systemic lupus erythematosus. The rate of depression identified in the study was also higher than previously identified rates of depression in patients with other neurological diseases, including dementia (30.3%), amyotrophic lateral sclerosis (34%), multiple sclerosis (30.5%), and mild cognitive impairment (32%), although the rate was lower than that in patients with Alzheimer disease (42%).
Subgroup analysis, which accounted for instrument, severity, study continent, duration of disease, and type of study, showed that the prevalences of mild, moderate, and severe depression were 27%, 14%, and 9% respectively.
Across the studies, there was a wide range of impact. The prevalence of depression ranged from 1% to 76% by individual study and the prevalence of anxiety ranged 3% to 71% by individual study.
This heterogeneity, explained the researchers, may be the result of different methodological approaches and screening tools used in each study. The most used screening tools for anxiety were the Beck Anxiety Inventory and the Hospital Anxiety and Depression Scale (HADS) and for depression, the Beck Depression Inventory and HADS—all of which have demonstrated validity and reliability in previous studies.
Writing of other limitations of the study, the researchers explained, “Some of the included studies used self-report questionnaires to assess anxiety and depression in MG patients, which can decrease the reliability of the results. Finally, the possibility of publication bias could not be fully ignored.”
Nadali J, Ghavampour N, Beiranvand F, et al. Prevalence of depression and anxiety among myasthenia gravis (MG) patients: a systematic review and meta-analysis. Brain Behav. Published online December 10, 2022. doi:10.1002/brb3.2840