Cognitive Impairment in Aging Bipolar Disorder: Clinical Profile, Risk Factors, and Differentiation from Neurodegenerative Dementia - A Case Report and literature review

Introduction: Bipolar disorder (BD) in older individuals is frequently associated with cognitive impairment; nevertheless, the attributes, trajectory, and specificity of this deterioration remain contentious. The investigation into a bipolar disorder-specific dementia pattern is hindered by confounding variables, including comorbidities, polypharmacy, and concomitant neurodegenerative processes. Methods: We describe a detailed case study of a 64-year-old patient with a 17-year history of bipolar disorder, characterized by persistent cognitive impairments. Along with this, there is a long narrative overview of the literature on cognitive trajectories, risk factors, pathophysiological mechanisms, and differential diagnosis in bipolar disorder in older adults. Results: The index case demonstrates a unique cognitive profile marked by pronounced psychomotor retardation, executive dysfunction, attentional impairments, and memory impairment, in contrast to relatively preserved Mini-Mental State Examination (MMSE) scores. Literature synthesis reveals that cognitive decline is contingent upon age, intensifying post-45 years, with a rapid advancement subsequent to 65 years. Several risk variables were identified: recurrence of mood disorders, frequency of hospitalization, early-onset mania, late-onset depression, psychotic characteristics, suicide attempts, and medical comorbidities. Neuropathological hypotheses include the decrease of frontal gray matter, altered Brain-Derived Neurotrophic Factor (BDNF) signaling, and the activation of inflammatory pathways. Conclusions: Currently, the factors explaining, or even predicting, a "dementia-like" progression in aging bipolar patients are uncertain. Screening and preventing cognitive impairment therefore seem all the more important, as it is crucial to offer tailored and patient-specific care.