The Relationship between Workaholism, Well-Being and Performance: A Cross-Sectional and Longitudinal Perspective Involving Subjective and Objective Measures

In the past decades, many changes in the work context (e.g., the increasing use of technology, the constant 24-hour availability of workers, high job demands, and high-performance expectations) have contributed to the spread of workaholism, namely, the individual tendency towork excessively and compulsively (Schaufeli et al., 2008). Interest in workaholism has grown among scholars over the years, emphasizing its negative consequences such as burnout (Clark et al.,2016) and sleep disorders (Kubota et al., 2014). However, there are still open questions about the underlying mechanism linking workaholismto some of the most significant variables for organizations and employee well-being (i.e., job performance, exhaustion, and job-related positiveaffect). Furthermore, research on workaholism has mainly considered this phenomenon a between-person variable, neglecting its potentialvariability within individuals (Clark et al., 2021). In line with these considerations, this doctoral thesis aims to answer some research questions: a) why workaholism is related to job performance (Study 1). b) Why workaholism is related to exhaustion (the main component of burnout; Study 2). c) Why workaholism is negatively related to job-related positive affect (Study 3). Chapter 1 provides an overview of workaholism by examining its definitions, antecedents and outcomes, measurements, and the theoreticalapproaches adopted in its conceptualization. Chapter 2 is based on Study 1. The first study focused on a cross-sectional survey of 389 Italian workers. Consistent with achievement motivation theory (McClelland, 1958, 1961) and the Work, Non-Work and Sleep (WNS; Crain et al., 2018) model, we hypothesized that workaholism is related to job performance through two opposing mediators: work engagement and sleep disorders. Chapter 3 is based on Study 2. 123 Italian workers participated in a diary study over ten working days. Consistent with affective event theory (Weiss & Cropanzano, 1996) and adopting a multilevel approach, we propose that job-related negative affect mediates the relationship between workaholism and exhaustion at the within-subject and between-subject levels. Chapter 4 is based on Study 3. 41 Italian workers wore an actigraph on their non-dominant arms for ten workdays while completing a diary survey. Drawing from the cognitive-energy model (Zohar et al., 2003, 2005) and using a multimethod approach (subjective and objective measures), we hypothesized a negative indirect effect of daily workaholism on daily job-related positive affect through daily sleep duration (within-subject level). Chapter 5 summarizes the main findings of the three studies and outlines theoretical and practical implications for future directions in workaholism research. Finally, in Chapters 6 and 7, the doctoral thesis is summarized in Italian and Spanish to comply with the agreement for joint supervision of the doctoral thesis.