Impaired insight in Alzheimer disease: association with cognitive deficits, psychiatric symptoms, and behavioral disturbances

The purpose of this study was to evaluate symptoms associated with impaired insight in patients with Alzheimer disease (AD). Although unawareness of deficits is common in AD, the relation of awareness to psychiatric and behavioral disturbances has not been extensively studied. We conducted a cross-sectional investigation of 91 patients with probable AD according to the criteria of the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association. Awareness of cognitive and functional deficits was measured with the Inaccurate Insight item from the Neurobehavioral Rating Scale. Psychiatric and behavioral symptoms were measured using factor scores and individual items from the Neurobehavioral Rating Scale. Global cognitive deficits were measured using the Mini-Mental State Examination (MMSE). Stepwise regression analysis showed that insight was associated with MMSE score, depression/anxiety factor score, and agitation/disinhibition factor score. Variables not associated with awareness of deficits included patient age, behavioral retardation factor score, verbal output disturbance factor score, and psychosis factor score. Post hoc analyses showed a positive relation (i.e., greater insight, more symptomatology) between deficit awareness and symptoms of depressed mood and anxiety. There was a negative relation (i.e., greater insight, less symptomatology) between insight and symptoms of hostility, agitation, inattention, and tension. In a follow-up stepwise regression analysis, increased deficit awareness was associated with a higher MMSE score, greater depressed mood, and decreased agitation. These findings suggest that patients with AD may experience symptoms of depressed mood in relation to increased awareness of decrements in functioning. The data also indicate that patients with poor insight demonstrate greater agitated behavior. Consistent with previous research, impaired insight was higher in the later stages of the illness.