Diabetes mellitus (DM) is known to be one of the risk factors for cognitive decline and dementia. Neuropsychiatric symptom (NPS) is present not only in dementia, but also mild cognitive impairment (MCI). In this study, we examined NPS of MCI with DM and compared MCI with DM and our MCI database to investigate the characteristics of MCI with DM.

The participants were subjects who were diagnosed as MCI from type 2 DM participants enrolled in Osaka University Hospital. To estimate NPS, we used Neuropsychiatric Inventory (NPI) score.

The number of MCI subjects with DM who were estimated NPS was 19. According to the NPI score, apathy is the most severe symptom in MCI (average score = 2.5±3.3). This result was the same as the score of our database. In the frequency of NPS, there was no difference between the results in NPI of MCI with DM and MCI of our data (n = 225) except for sleep disturbance and appetite/eating disturbance (chi-squared test, P < 0.05). The sleep disturbance was more frequent in MCI with DM than in MCI of our database. On the other hand, the appetite/eating disturbance was less frequent in in MCI with DM than in MCI of our database. Moreover, the appetite/eating disturbance was not observed in MCI with DM.

NPS of MCI with DM is almost the same as MCI of our database except for sleep disturbance and appetite/eating disturbance. This result might be influenced by the disorder of lifestyle habits that is often observed in patients with DM or cognitive impairment of DM.

The limitation of our study is the small number of cases, further investigation is needed.