Psychometric Evaluation of the Lithuanian Version of the Revised Compound Psychological Capital Scale (CPC-12R) and Its Associations with Nature Exposure and Physical Activity

Psychological capital (PsyCap), comprising optimism, hope, self-efficacy, and resilience, is an important positive psychological resource associated with well-being and adaptive functioning. The present study aimed to evaluate the psychometric properties of the Lithuanian version of the revised Compound Psychological Capital Scale (CPC-12R) and to examine its associations with nature exposure and physical activity. A cross-sectional survey was conducted among 1255 Lithuanian adults aged 18–70 years (mean age 39.51 ± 13.84 years), and 64.4% were women. The total sample was randomly divided into exploratory (n = 628) and confirmatory factor analysis (n = 627) subsamples. Exploratory factor analysis supported a two-factor structure separating optimism from the remaining CPC-12R dimensions, whereas confirmatory factor analysis supported the theoretically expected second-order model comprising optimism, hope, self-efficacy, and resilience as first-order factors reflected by a higher-order PsyCap construct. The second-order model demonstrated good fit (robust CFI = 0.963, robust TLI = 0.952, robust RMSEA = 0.074, SRMR = 0.042) and strict measurement invariance across gender and place-of residence groups. Internal consistency was satisfactory to good for all subscales (McDonald’s ω = 0.79–0.85) and excellent for the total scale (ω = 0.93). Evidence of convergent validity was demonstrated through positive associations with self-esteem and life satisfaction and negative associations with psychological distress and poorer mental health. Furthermore, PsyCap explained a small but significant proportion of additional variance in mental health difficulties beyond self-esteem, life satisfaction, and psychological distress. PsyCap was positively associated with nature exposure, physical activity in nature, and leisure-time exercise. Hierarchical regression analyses indicated that greater nature exposure and more frequent physical activity in nature were independently positively associated with PsyCap after accounting for sociodemographic characteristics, whereas leisure-time exercise was not. Overall, the findings support the reliability and validity of the Lithuanian CPC-12R, particularly its total score, although the EFA results suggest caution when interpreting the four subscale scores separately. The cross-sectional findings further identify engagement with natural environments as a meaningful behavioural correlate of PsyCap.