Some studies suggest that abnormal behaviors are associated with increasing cognitive loss in Alzheimer's disease (AD). Other studies do not show this association. We examined the relation of cognitive loss, represented by Folstein Mini-Mental State Examination (MMSE) score, with abnormal behaviors in 680 patients with probable AD. Six behaviors were examined: agitation/anger, personality change, wandering, hallucinations/delusions, insomnia, and depression. All but depression were associated with declining MMSE score. The number of abnormal behaviors present in each patient was also related to declining MMSE score. Several other associations were also found: hallucinations/delusions were associated with age and race; agitation/anger was related to male gender; and wandering was associated with increased age. Although these data support the general notion that five of the six abnormal behaviors studied are more likely to occur with increasing cognitive loss, the correlations are small and it is suggested that other as yet unproven factors may play an as large or greater role than MMSE score in predicting such behaviors.