Problematic smartphone use and wellbeing: The roles of screentime and impulsivity

Hughes, Sarah 2025. Problematic smartphone use and wellbeing: The roles of screentime and impulsivity. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

There has been a growing level of concern surrounding the potential implications of increasing levels of smartphone use, particularly as ownership and dependence continues to rise. The overall purpose of this PhD is to investigate the relationship between screentime, problematic smartphone use, impulsivity and wellbeing, and to evaluate the potential effectiveness of app-based, digital behaviour-change interventions in reducing problematic smartphone use and improve wellbeing. This PhD addresses these aims by conducting two empirical studies. The first study in this thesis uses a cross-sectional survey (N = 424) to examine associations between various forms of screentime (estimated, objective, and self-reported), problematic smartphone use, impulsivity, and wellbeing outcomes, including subjective wellbeing (positive and negative affect), psychological wellbeing and perceived connectedness. Results suggest that higher screentime is associated with higher levels of problematic smartphone use. which was negatively related to subjective wellbeing, psychological wellbeing and connectedness. However, the results provide only partial support for the prediction that screentime would have a negative effect on wellbeing. Problematic smartphone use partially mediated the relationship between screentime and negative emotions; however, this was not significant for positive emotions. Impulsivity only moderated the relationship between screentime and positive emotions, connectedness and psychological wellbeing. Additionally, impulsivity did not significantly moderate the relationship between screentime and problematic smartphone use or problematic smartphone use and wellbeing, though a direct effect of impulsivity on problematic smartphone use was observed. Study 2 uses a longitudinal experimental study (N= 87) to investigate the effectiveness of an app-based digital behaviour-change intervention in reducing screentime, problematic smartphone use, and improving wellbeing. Although screentime reductions were reported by the intervention group, these were not found to be statistically significant. However, significant reductions are reported for levels of problematic smartphone use. The role of impulsivity as a moderator of intervention effectiveness was not supported. Contrary to expectations, no significant improvements were found in psychological or subjective wellbeing, and a small decrease in positive emotions was observed in the intervention group. Changes in screentime did not significantly influence wellbeing outcomes. However, increases in levels of problematic smartphone use were significantly associated with increased negative affect. ii This thesis contributes new insights into the relationship between screentime, problematic smartphone use, impulsivity, and wellbeing, demonstrating that problematic smartphone use plays a role in predicting negative wellbeing outcomes than screentime alone. The findings also address the gap in current literature by exploring the moderating role of impulsivity in the relationship between screentime and problematic smartphone use. Key words: Problematic smartphone use, screentime, impulsivity, psychological wellbeing, subjective wellbeing, connectedness, digital behaviour change intervention

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Business (Including Economics)
Subjects:	H Social Sciences > H Social Sciences (General)
Uncontrolled Keywords:	Problematic smartphone use, screentime, impulsivity, psychological wellbeing, subjective wellbeing, connectedness, digital behaviour change intervention
Date of First Compliant Deposit:	21 October 2026
Last Modified:	21 Oct 2026 09:21
URI:	https://orca.cardiff.ac.uk/id/eprint/190267

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