The present study evaluates the impact of subjective theories of illness in patients suffering from Myasthenia gravis. 46 inpatients were examined after the diagnosis had been made (T1) and 6 months later (T2). The following instruments have been used: a semistructured interview, the ¿Freiburg Personality Inventory¿ (FPI), the ¿Freiburg Questionnaire of Coping with Illness (FKV) and a questionnaire for the judgement of body experiences (FBK). Ratings concerning neurotic symptoms (PSKB), mechanisms of defence (KBAM) and the doctor-patient-relationship were made by the interviewers and the treating neurologist as well. 35% of the patients experienced a connection between psychosocial factors (stress) and the onset of the disease. As compared with those patients not showing a psychosocial causal attribution there are no differences in somatic (type and severity of the disease, thymus histology), but in psychological variables. Patients attributing their disease to psychosocial factors prove to be more depressive, insecure and excitable at T1. They are more likely to be women. These findings are in accordance with the results of previous studies. However, 6 months later (T2) there is some evidence of a psychological stabilization of those patients using psychosocial attributions, as different instruments show concurrently. Partially they appear now even less depressive. This result is understood as a hint for the significance of emotional factors for the process of coping with the disease: patients using a psychosocial explanation concept may appear more vulnerable at an early stage of the disease. But perhaps, by this more emotionally centered coping process, they can reach stability which is connected with the construction of a psychosocial theory of the disease.