Within the framework of interactional theories of depression it was examined whether the interaction of 31 severely depressed patients and a psychiatrist was related to the course of depression during hospitalization. Interactional processes were defined on the basis of directly observed behaviour displayed during an interview and by the use of ethological methods. The behavioural structure of such interaction could be described by 6-7 factors. Some of these factors could predict the clinical course of depression, over an interval of tien weeks. The patients who would not improve displayed before treatment (just after admission) more involvement (i.e., looking, gesticulating) coinciding with more general activation (leg and hand movements) than the patients who would improve. The psychiatrist displayed relatively high levels of involvement (encouragement: hm, hm, yes, yes, and yes-nodding) and low levels of general activation (hand movements) in his interaction with patients who would not improve. The results provide support for interactional theories of depression.
