Introduction: People with young-onset Alzheimer’s disease (YOAD) are diagnosed when the neurocognitive process begins before the age of 65 and often present with more global impairments and a more rapid course of the disease. In contrast, in late-onset Alzheimer’s disease (LOAD), the loss of short-term memory is most pronounced. Therefore, the age of onset may affect global functioning in different ways.

Objectives: This study examines the relationship between Social Cognition, global cognition, and other clinical variables in young and late-onset people with Alzheimer’s disease and their caregivers.

Methods: Using a cross-sectional design, we included 48 people with YOAD and 118 with LOAD and their carers. We assessed social cognition, global cognition, quality of life, dementia severity, mood, functionality, neuropsychiatric symptoms, and caregiver burden.

Results: Our results showed that the YOAD group had more global cognitive impairment, lower MMSE scores (P = 0.018, d = 0.41), higher Adas cog (P = 0.002, d = 0.06), poorer quality of life (QoL- AD) (P = 0.036, d = 0.36), and more neuropsychiatric symptoms (NPI) (P = 0.044, d = 0.35). However, social cognition showed a stable pattern of impairments in YOAD that did not follow the global deficits. The multifactorial regression analyses further showed that in both groups functionality was significantly related to Social Cognition, YOAD (P = 0.035), and LOAD (P = 0.001).

Conclusions: The significant findings of our study underscore that in YOAD, despite more pronounced global impairment compared to LOAD, social cognition remains stable. This finding is crucial for understanding the patterns of social cognition in YOAD and may potentially guide future interventions and care strategies.