Daily loneliness deconstructed: Examining patterns of within- and between-person variation.

There is growing interest in examining loneliness using intensive repeated assessment methods in daily life; however, much remains unknown regarding variation in loneliness at the within- and between-person level. Better characterizing dynamic daily experiences of loneliness will help clarify the nature of loneliness experiences that may be indicative of current and future risk for chronic loneliness and provide information to inform future study designs. We characterized daily loneliness among an online sample of 98 adults (23-78 years, 55% women, generally healthy) who completed daily surveys for 14 consecutive days (N_observations = 1,330). Participants were systematically recruited in 2024 based on loneliness status categories (41 chronically lonely, 27 acutely lonely, and 30 nonlonely) derived from Patient-Reported Outcomes Measurement Information System measure scores and self-reported duration. We compared the following for each group: (a) average levels of daily loneliness, (b) the proportion of within- versus between-person variance in daily loneliness, and (c) indicators of within- and between-person daily loneliness variability. Analyses revealed that lonely individuals overall (both chronic and acute) reported higher levels of average daily loneliness than nonlonely individuals. Furthermore, despite self-reporting similar levels of traitlike loneliness (Patient-Reported Outcomes Measurement Information System measure) and average daily loneliness as acutely lonely individuals, chronically lonely individuals had a higher proportion of within-person variance and greater within-person variability in daily loneliness. Findings offer a starting point to disentangle how within-person variability of loneliness in daily life may play a role in the development and maintenance of chronic loneliness over time. (PsycInfo Database Record (c) 2026 APA, all rights reserved).