Delusions of Korean patients with Alzheimer's disease: Study of drug-naive patients

Aim: Although delusions are one of the most prominent psychiatric symptoms in Alzheimer's disease (AD), research on the subtypes, prevalence and associated factors of delusions, especially in drug (psychotropic)-naive patients, has been limited. Methods: Patients (n=230) with psychotropic-naive (drug-naive) probable AD were assessed with the Korean Neuropsychiatric Inventory (K-NPI) delusion subscale at the time of initial presentation. After determining the four delusion subtypes (paranoid, misidentification, mixed and expansive delusion), clinical characteristics and prevalence of each type were compared. Results: Delusions were present in 63 patients (27.4%). Among those patients, paranoid delusions were the most common type of delusion (38, 60.3%), followed by misidentification delusions (12, 19.0%), then mixed delusions (11, 17.5%). Expansive delusions are rare in drug-naive probable AD patients. Compared with paranoid delusions, misidentification and mixed delusions appeared at a later stage, and were associated with greater cognitive impairment. Mixed delusions were associated with hallucinations. Conclusions: This study showed that delusions are associated with global cognitive dysfunction. Although paranoid delusions are the most common, misidentification and mixed delusions comprised significant portions of delusions in AD patients, and appeared in the later stages of dementia. Geriatr Gerontol Int 2013; 13: 307313.