[The influence of psychic stress on the clinical manifestations and course of myasthenia gravis].

An aim of the study was to evaluate whether psychic stress influenced clinical manifestations and course severity in patients with myasthenia gravis (MG). Seventy-three patients with proven MG (mean age 36,6; SD 13,7 years) and 112 healthy controls (mean age 38,3; SD 10,3 years) were included in the study. The Myasthenia Symptoms Severity Scale was specially elaborated for MG symptoms quantitative assessment. Pneumotachimetric pulmonary functions, including forced expiratory volume in 1 sec (FEV1) and psychological characteristics (short version of MMPI test, Spilberger Anxiety Inventory, Zung Self-Rating Depression Scale (SDS), were measured in each patient. The main causes of daily stress by means of a special self-questionnaire were ascertained and assessment of disability severity was scored. The first examination (T1) was followed up by a second one (T2) 12 months later. In each patient, disease course was specified as mild, moderate or very severe during the T1-T2 period. In most patients (60%), the development or decompensation of MG was caused by psychogenic stressors. Reactive and personal anxiety as well as SDS index were higher in patients as compared to healthy subjects (p<0,001). There was no association between any of personality traits and MG but the patient's average personality profile was elevated comparing to the control group that suggested a presence of mild chronic stress. The main causes of daily stress were related to the consequences of MG. Reactive anxiety was correlated with myasthenia symptoms severity scores and disability scores in patients (p<0,05). The prognostic significance for severe MG course was estimated for the myasthenia symptoms severity score, reactive anxiety (more than 55 scores) and FEV1. The results obtained suggest that psychotherapy seems to be most useful for patients with severe myasthenia symptoms and high psychic stress.