Impulse Dyscontrol Symptoms Are Related to Amyloid Beta in Patients With Subjective Cognitive Decline and Mild Cognitive Impairment.

INTRODUCTION: The relationship between neuropsychiatric symptoms (NPSs) and Alzheimer's disease (AD) pathophysiology, considering cerebrospinal fluid (CSF) biomarkers, is still not clarified and the available results in the literature are contradictory especially when it comes to the prodromic stages of AD. Clarifying the role of the AD biomarkers in the development of NPS in subjective cognitive decline (SCD) and mild cognitive impairment (MCI) is relevant and can be useful for planning longitudinal interventions in the AD continuum. The present work studies the correlation between NPSs and AD CSF biomarkers in SCD and MCI Brazilian subjects. METHODS: This is a transversal study designed to evaluate the relationship between NPS and CSF AD biomarkers in SCD and MCI individuals. Voluntary participants were recruited through a virtually announced formulary. The inclusion criteria were age 55 years or older, of both sexes, without distinction of ethnicity or socioeconomic status, the presence of cognitive complaints, and that were willing to participate in all research procedures. Exclusion criteria for all subjects included clinical dementia, other neurological or psychiatric diseases, traumatic brain injury that resulted in a loss of consciousness, drug or alcohol addiction, prior chronic exposure to neurotoxic substances, Fazekas scale ≥ 2, and a score on the Montreal Cognitive Assessment (MoCA) less than 17 points. All participants had Pfeffer's Functional Activities Questionnaire < 5 and underwent medical and neuropsychological evaluation. RESULTS: Seventy-one patients were included between 2019 and 2022, 54 with MCI and 17 with SCD. A significant correlation (p: 0.006) was observed between MBI-C C domain and the concentrations of CSF amyloid-beta peptide. CONCLUSION: The study identified a significant correlation between domain C of the MBI-C and CSF beta-amyloid peptide analysing Brazilian patients with SCD and MCI. The results reinforce the hypothesis of the relationship between impulsivity symptoms and amyloid pathology. Further studies involving the correlations between MBI and neuropsychiatric symptoms with AD CSF biomarkers are necessary.