With the growing prevalence of health and illness narratives on digital platforms, research examining the social psychological processes involved in these storytelling environments remains scarce. This paper addresses this research gap by conducting a mixed-methods study of digital storytelling within the UK’s healthcare context, focusing on online consumer reviews of the medical memoir, Do no harm: stories of life, death and brain surgery (Marsh, 2014). Utilising computer-assisted text analysis methods of LIWC-22 and the Sketch Engine, linguistic cues for cognitive, affective, social and perceptual processes are identified in a corpus of online consumer reviews. A subsequent qualitative analysis, based on ‘narrative modulation’ (Huang, 2024, 2020), investigates the role of these processes in constructing and developing storylines across the user reviews. Finally, the study explores how consumer reviews in the form of ‘small stories’ challenge canonical narratives in the UK’s healthcare services. This research advances the field of narrative studies by emphasising the role of social psychological processes (Chung and Pennebaker, 2019) in modulating emerging, evolving and counter narratives in digital storytelling. The findings reveal an instrumental role of social psychological processes, as signalled by linguistic cues, in shaping narrative threads in online user reviews. This study not only develops narrative modulation as a valuable concept for narrative analysis, but also underscores its effectiveness when combined with computer-assisted text analysis tools for in-depth examinations of narrative data. Furthermore, it provides critical insights into digital storytelling in healthcare contexts, promoting knowledge transfer across narrative studies, stylistics, social psychology and medical humanities.