Mild behavioral impairment (MBI) is a validated diagnostic entity, that describes the emergence of later life neuropsychiatric symptoms (NPS) in pre-dementia states. The aim of this study was to estimate the prevalence of MBI in people with subjective cognitive complains (SCCs) in primary care centers and observe the evolution in a longitudinal study.

Three hundred twenty-three participants belonging to the CompAS longitudinal study who attended primary care centers with SCCs and without previous diagnosis of dementia and other neurological or psychiatric disturbances underwent clinical, neurological, and neuropsychological examinations at baseline and at two follow-up times (around 24 and 60 moths). At each evaluation point participants were diagnosed as Cognitively Unimpaired (UC), Mild Cognitive Impairment (MCI) and SDC; at the follow-up assessments dementia was diagnosed as well. Diagnosis of MBI was made via a series of semistructured independent interviews with patients and relatives in accordance with the ISTAART-AA criteria and using the Spanish MBI-C cut-off point (Mallo et al, 2019). Frequencies of participants diagnosed in each category were obtained and evolution of the MBI along the follow-up evaluations was studied.

MBI diagnosis prevalence was 22.9% at baseline corresponding to 74 individuals of which at 24 months follow-up were MBI stable 31.1%, 14.9% evolved to MCI, 1.3% to dementia and 40% to CU, (attrition 12.2%). At 60 months follow-up, from the 23 individuals with MBI, 6 remained stable (26.1%), 6 (21.1%) evolved to MCI, 2 (8.7%) to dementia, 3 (13%) to CU, (attrition 26.1%) (Figure 1).

Results indicated that almost a quarter of individuals attending primary care centers with SCCs without previous diagnosis of dementia or psychiatric disorders are MBI. An important part of them evolve to UC or MCI, and only a minority progress to dementia. More studies are needed to analyze the cognitive, personal, and biological factors that determine this evolution.