Delusions of theft in dementia of the Alzheimer type: a preliminary report.

Delusions of theft are commonly found in patients with dementia of the Alzheimer type (DAT). This report describes the frequency, onset, and characteristics of delusions of theft in DAT patients. The sample consisted of 54 geropsychiatric inpatients with DAT; delusions of theft were found in 30 (55.6%) patients. Two thirds of these patients had delusions of theft within 1 year after onset of illness. There were no significant differences in age, age of onset, duration of disease, years of education, or the Mini-Mental State Examination (MMSE) score between patients with and without delusions of theft. Delusions of theft frequently occur in the early stage of dementia, when the patients' cognitive impairments are relatively mild. The presence of this symptom may warrant a diagnosis of DAT.