The frequency of the manifestation of delusions and hallucinations (d/h) among participants of adult day care centers was examined, as was the relationship of d/h to demographic and medical variables, agitation, depressed affect, and dementia. Changes in d/h were also assessed over a 1- year period, and those changes were compared with changes in agitation, depressed affect, and dementia. Depressed affect and agitation were related both to delusions and to hallucinations. Dementia was also related to d/h, although a substantial percentage of individuals who were not diagnosed with dementia also experienced some type of d/h. Finally, delusions were more prevalent and generally tended to relate more strongly to agitation, depressed affect, and dementia than did hallucinations.