A family atmosphere characterized by expressed emotion (EE) is a robust predictor of clinical outcome of patients with schizophrenia and mood disorders. However, there is ongoing discussion as to whether EE is more a cause of clinical outcome or a parental reaction to disorder severity. This cross-sectional study examines a sample of 42 consecutive first-episode patients from a defined geographical area with severe mental disorders (schizophrenia-related disorders, psychotic mood disorders, and non-psychotic mood disorders). Their 42 relatives were interviewed, and the relationships between EE variables derived with the five-minute speech sample method (FMSS) and the patients’ demographic, premorbid and clinical measures were analyzed. A high EE score was found in 40% of the relatives. High EE was associated with the interviewed relative's not being a spouse and the patient's being young and unmarried. It was not associated with premorbid characteristics, symptom dimensions or the diagnostic group of the patient. These results do not support the hypothesis that EE is a reaction to the clinical features of the patient. Instead, demographic factors may partly mediate the effect of EE on prognosis.