Eight experienced qualities of reality were examined in relation to five sorts of experience in 15 demented patients in clear states of consciousness (the CSC group), and in 15 patients in disturbed states of consciousness (the DSC group). Many more abnormal reality qualities appeared in the DSC than in the CSC group. In the DSC patients the tendency to experience non-existent fantasy items as being real was so much greater than in the CSC patients that it will be of value in differential diagnosis if it is confirmed in other patient materials. In DSC patients, furthermore, positive qualities of sensation were found attached to many experiences of items which were not present in the actual stimulus fiels - even in patients who were not clinically hallucinated. The reliability of the results was controlled by having each patient evaluated by two psychiatrists.