Introduction: Alzheimer’s disease (AD) and mild cognitive impairment (MCI) are widely recognized for their hallmark cognitive deficits, typically characterized by progressive cognitive deterioration. However, neuropsychiatric symptoms (NPS) including depression, apathy, anxiety, irritability, and sleep disturbances are increasingly prevalent in early stages of these conditions and significantly influence disease trajectory and patient outcomes. Importantly, neuropsychiatric symptoms often precede overt memory loss by several years, with subtle mood and behavioral disturbances serving as early pre-diagnostic markers of underlying Alzheimer’s pathology. Their presence complicates diagnosis, accelerates disease progression, and intensifies caregiver burden. However, distinguishing NPS arising from neurodegeneration from primary psychiatric disorders remain a profound diagnostic challenge, delaying timely intervention and obscuring early disease recognition.
Methods: A structured narrative review of peer-reviewed studies published between 2012 and 2025 was conducted using PubMed, MEDLINE, Scopus, PsycINFO, Google Scholar, and CINAHL to examine the diagnostic complexities, clinical impact, and current management of NPS in early-stage AD and MCI. We argue that understanding and managing NPS is essential to improving clinical outcomes and guiding therapeutic innovation.
Findings: NPS affects up to 80% of individuals with early AD or MCI, often preceding cognitive decline. Current management strategies rely heavily on non-pharmacological interventions such as caregiver support, behavioral activation, and structured routines, while pharmacological options remain limited by modest efficacy and safety concerns. Advancing knowledge of neuropsychiatric symptoms (NPS) and their association with cognitive decline is critical for establishing more precise diagnostic criteria and for informing personalized therapeutic approaches.
Conclusions: Not understanding the role and impact of neuropsychiatric symptoms in early-stage AD and MCI may have serious clinical, personal, and societal consequences. It may lead to delayed diagnosis, poor patient care, and increased caregiver stress and hampers both research and innovation. Recognizing NPS as early and integral features of disease progression is essential for transforming the diagnosis, care, and treatment of dementia-related disorders.
