Re-examined how psychiatric patients' perception by their treatment setting was related to locus of control, unconfounded by variations in treatment setting, differences in pathology, or length of hospitalization. Forty male patients were drawn from the general psychiatric' population of Norwich Hospital. They were administered the Rotter I-E Scale, Ward Atmosphere and Ward Initiative Scales. In contrast to reports found in the literature, the results of the study indicated that internally oriented patients preferred a well-ordered, organized treatment setting in which therapeutic objectives and treatment procedures were defined clearly. A most important determinant of the perception of the treatment setting appeared to be the Internals' personal involvement in the therapeutic functioning of the unit. Externals felt that the level of personal participation in the operation of the unit should be minimal and that treatment plans and procedures should be formulated by professional staff and not by their peers.