To evaluate qualitative differences in the nature of thought disorder, the ‘cloze’ procedure and the Scale for the Assessment of Thought, Language and Communication were used to compare speech samples from schizophrenic, depressive, manic, schizo-affective and normal subjects at two different times. At the acute phase, thought-disordered subjects (schizophrenics, manics and schizo-affectives) were less communicable than non-thought-disordered subjects (depressives and normals). Communicability increased with remission of the more flagrant features of disturbance. Comparison of the thought-disordered diagnostic groups in the rate and pattern of remission of specific features of thought disorder indicated that factors reflecting goal-disrupted cognition distinguished the groups.