Material and Method: The present study is a cross-sectional descriptive design. The participants comprised 62 patients from the Memory Clinic at Thammasat University Hospital, Thailand. Subjects were diagnosed as having Alzheimer’s disease according to the National Institute of Neurological and Communicative Disorders and Stroke and Alzheimer’s disease and Related Disorders Association (NINCDS-ADRDA) criteria and received global Clinical Dementia Rating scale (CDR) score of at least stage 1. All participants were assessed using the Neuropsychiatric Inventory Questionnaire (NPI) and the Thai Mental State Examination (TMSE).

Results: The subjects were female 62.9% and male 37.1%, the mean age was 76±6.7 years. The majority of them (62.9%) were in the mild stage (CDR = 1). The result showed that the prevalence of neuropsychiatric symptoms (≥1 symptom) reported was 100%. The most common symptoms were apathy (71%), aberrant motor behavior (61.3%), sleep problems (56.5%), eating problems (51.6%) and agitation/aggression (45.2%), whereas the least was euphoria (6.5%). The number of neuropsychiatric symptoms increased with severity of the disease. The result also showed that 61.3% of the participants presented with the chief complaint of neuropsychiatric symptoms, whereas memory complaints were only 38.7%.

Conclusion: Neuropsychiatric symptoms are very common in Thai Alzheimer’s disease patients. Therefore, management of Alzheimer’s patients should include an assessment of neuropsychiatric symptoms and also concentrate on reducing these symptoms. The number of neuropsychiatric symptoms increases with disease progression. Moreover, neuropsychiatric symptoms were the most common presenting problem rather than memory problem in Thai patients with Alzheimer’s disease.

Keywords: Prevalence, Dementia, Alzheimer’s disease, Behavioral symptom, Neuropsychiatric symptom