Patients with major neurocognitive disorder due to Alzheimer's disease have diverse clinical manifestations and courses. Some patients visit the clinic because of pure cognitive impairments such as memory impairment, however many patients are forced to visit the clinic by their caregivers because of their behavioral changes. In this study, we tried to overview the first symptoms at their diagnostic period and progress of cognitive impairment. We enrolled the patients who started to take cholinesterase inhibitors for treatment of major neurocognitive disorder due to Alzheimer's disease and mixed etiology including Alzheimer's disease from psychiatric department of our hospital from November 2014 to October 2015. We reviewed the symptoms at the diagnostic time of major neurocognitive disorder and the scores of Mini Mental State Examination (MMSE) and Clinical Dementia Rating (CDR) for three consecutive years. All subjects were diagnosed by psychiatrists based on Diagnostic and Statistical Manual of Mental Disorders, Fifth edition (DSM-V). Psychiatrists and trained nurses checked MMSE and CDR every year. We reviewed 148 subjects, and 112 subjects (75.7%) were female (mean age; 77.88 (SD 7.79)). Fifty four subjects (36.5%) had psychotic symptoms, and 121 subjects (81.8%) had any BPSDs at the time of diagnosis of dementia. The subjects with BPSD had higher MMSE total score in the second (p<0.01) and the third year (p<0.01). The subjects with psychotic symptoms had similar MMSE total scores with the subjects without psychotic symptoms; however they showed more decreasement than the subjects without psychotic symptoms, especially the subjects with delusion. Many patients who were diagnosed as major neurocognitive disorder d/t Alzheimer's disease and mixed etiology including Alzheimer's disease had BPSD at the time of diagnosis. The patients who had BPSD in early stage can visit the clinic with mild cognitive impairment. And the patients with psychotic symptoms such as delusion and hallucination showed faster deterioration. The clinicians should focus on BPSD including psychotic symptoms at the diagnostic period. The main limitation of this study is that we enrolled the patients from psychiatric department, so more subjects had severe BPSD including psychotic symptoms.