The prevalence of depression in myasthenia gravis

Conflicting results are reported regarding the prevalence of depression in myasthenia gravis (MG) compared to the general population. One suggestion is that the psychiatric instruments used to assess depression confounded symptoms of disease activity with common features of depression. OBJECTIVES: We investigated the prevalence of depression in MG using psychiatric instruments that allowed for delineation between a patient's medical and psychological state. METHODS: Thirty-six patients with MG and 20 patients with neurologic and neuromuscular diseases (NNMD) were evaluated with 3 self-administered depression scales and a psychiatric interview. RESULTS: Patients with MG had a similar prevalence of depression as that of patients with NNMD. Both groups showed a higher prevalence of depression compared to the general population, which was a frequency similar to a population with chronic illness. No difference was observed between the 2 groups in the physical symptoms of depression. CONCLUSION: This suggests the physical symptoms of depression do not influence the depression rates in MG when compared to NNMD.