Although emotional blunting has always been considered a core symptom of schizophrenia, it has been excluded from recently developed sets of diagnostic criteria because of its alleged unreliability. The authors describe a brief rating scale for emotional blunting that is highly reliable, predicts short-term treatment response, and discriminates between patients with affective disorder and schizophrenia. They suggest that this scale will permit restoration of the important criterion of emotional blunting to modern diagnostic systems, including that proposed for DSM-III.