BackgroundThe containment measures linked to the COVID‐19 pandemic negatively affected the phyco‐physical well‐being of the population, especially older adults with neurocognitive disorders (NCDs). This study aims to evaluate whether the frailty of NCD patients was associated with different changes in multiple health domains, in particular in relation to loneliness and social isolation, pre‐ and post‐lockdown.Materials and MethodsPatients were recruited from 10 Italian Centers for Cognitive Disorders and Dementia. Data were collected in the pre‐pandemic period (T0), during the pandemic lockdown (T1), and 6–9 months post‐lockdown (T2). The UCLA Loneliness Scale‐3, Activities of Daily Living (ADL), Instrumental ADL (IADL), Mini‐Mental State Examination, and Neuropsychiatric Inventory (NPI) were administered. Caregivers' burden was also tested. Patients were categorized as non‐frail, pre‐frail, and frail according to the Fatigue, Resistance, Ambulation, Illness, and Loss of Weight scale.ResultsThe sample included 165 subjects (61.9% women, mean age 79.5 ± 4.9 years). In the whole sample, the ADL, IADL, and NPI scores significantly declined between T0 and T2. There were no significative variations in functional and cognitive domains between the frail groups. During lockdown we recorded higher Depression Anxiety Stress Scales and Perceived Stress Scale scores in frail people. In multivariable logistic regression, frailty was associated with an increase in social isolation, and a loss of IADL.ConclusionsWe observed a global deterioration in functional and neuro‐psychiatric domains irrespective of the degree of frailty. Frailty was associated with the worsening of social isolation during lockdown. Frail patients and their caregivers seemed to experience more anxiety and stress disorders during SARS‐CoV‐2 pandemic.