P3-468: effects of apoe e4 genotype and depression on cognitive functions in amnestic mild cognitive impairment and subjective cognitive decline

APOE e4 is a generic risk factor for incident AD and depression is also known to increase risk of AD. It still remains unclear, however, how depression and APOE e4 genotype interact differently in amnestic mild cognitive impairment (aMCI) and subjective cognitive decline (SCD). This study investigated the effects of depression and APOE e4 genotype on various cognitive performances in aMCI and SCD. Participants (N=1,306, 713 aMCIs and 593 SCDs) aged 50 and older who came to the memory clinic complaining cognitive declines from 2013 to 2017 were included retrospectively. The participants were classified into APOE e4 carriers (e3/e4 or e4/e4) or noncarriers (e3/e3). Presence of depression was defined by the total score > 7 in the Korean version of Geriatric depression scale-short form. Neuropsychological tests included confrontational naming, visuospatial construction, verbal memory, visual memory, semantic generative naming, phonemic generative naming, and inhibitory control. The three way ANCOVA with independent variables of APOE genotype (e4 carriers/noncarriers), depression (patients with/without depression), and diagnosis groups (aMCI/SCD) on the cognitive performances (z scores) were conducted with age, sex, and education as covariates. Effects of APOE genotype and depression were limited to performances in verbal and visual memory tests, and semantic and phonemic generative naming tests. On verbal delayed recall and visual delayed recall tests, APOE e4 carriers performed worse than the noncarriers. On phonemic generative naming, a main effect of depression was significant indicating patients with depression performed worse than those without depression. In addition, there was a significant interaction effect between the two patient groups (aMCI/SCD) and the presence of depression in semantic generative naming. In SCD depression had no effect on animal generative naming, while patients with depression showed lower performance than patients without depression in aMCI group. APOE genotype and depression differently interact with some of the cognitive domains. APOE e4 exacerbated the memory function, and depression affected the semantic and phonemic word fluency. In addition, it indicates that in certain cognitive test (semantic word fluency) depression can aggravate performances only of aMCI but not of SCD.