Participants of the RCT who completed all course modules, the precourse baseline survey, and postcourse evaluation survey across both study arms (n=53) were invited by email to participate in a 45-60 minute semistructured interview 1 month after completing the course (Multimedia Appendix 3). In total, 38 participants accepted the invitation. Written informed consent was obtained from all participants in the baseline survey, within the first MSOC module of the RCT, and verbal consent was obtained before participating in semistructured interviews purposed for qualitative analyses.

Demographic and clinical quantitative data presented in the current study were obtained from the pre-course baseline survey. The Hospital Anxiety and Depression Scale (HADS) [20] was reported to characterize the severity of self-reported depressive and anxiety symptoms. The HADS, used extensively in the population living with MS (eg, Dahl et al [21] and Janssens et al [22]), has demonstrated accurate sensitivity and specificity for major depressive disorder (90% and 87%, respectively) and generalized anxiety disorder (88% and 81%, respectively) within the population living with MS [23]. Ambulation levels were evaluated using the Patient-Determined Disease Steps (PDDS) scale [24], recognized as a guide of overall disability in individuals with mild-to-moderate disabilities due to MS [25].

Participants were invited by email to participate in semistructured interviews 1 month after completing the MSOC. Interviews occurred at a time convenient for participants between October 14, 2022, and November 16, 2022, and were conducted by SN (lead interviewer), RD, JR, and PJ using Zoom (Zoom Video Communications, Inc) software licensed by The University of Melbourne or WhatsApp (Meta). Interviewers had a research background and either (1) had substantial experience conducting qualitative research or (2) were highly trained health care professionals routinely involved in the clinical management of MS and other chronic diseases. There were minor variations in the interview scripts for the intervention versus the standard care group. Interview questions explored perceived changes in attitudes toward MS and health, initial health changes, and broader aspects of the course experience (eg, engagement with the online forum and views of course content; Multimedia Appendix 4).

To ensure consistency in the delivery of the interview schedule between interviewers, authors (RD, JR, and PJ) observed 1 interview conducted by the lead interviewer (SJ). Minor changes to the structure of the interview schedule were made following the 3 initial interviews with the intention of ensuring the schedule followed a coherent, logical order (eg, all questions probing mental health variables were asked consecutively). With participant permission, interviews were audio recorded and transcribed verbatim, using the voice recognition software Temi (Rev) [26]. Transcripts were saved in a restricted folder and were accessed by interviewers. Transcript text was altered for purposes such as upholding participant confidentiality by redacting sensitive disclosures as requested by participants and ensuring that text were a verbatim account participants’ verbal responses. Transcripts were imported into NVivo qualitative data analysis software (version 12, 2018; Lumivero [formerly QSR International]). In line with best-practice data management, document coding and theme development were maintained within NVivo outputs.

Inductive, reflexive thematic analysis was used as a means of identifying, analyzing, and reporting patterns in the data [27]. Reflexive thematic analysis was selected as it allows for researcher autonomy in the processes of determining themes (latent or semantic) and establishing the most relevant analysis to use (inductive vs theoretical). This study applied the 6 distinct phases of thematic analysis: data familiarization, generating codes, constructing themes, reviewing potential themes, defining and naming themes, and producing the report [28]. The dataset was divided into 2, according to the IC and SCC arms, and both were analyzed and coded independently by RD and WB, respectively.

Following data familiarization and coding, the research team met to review potential themes to ensure alignment with the raw data and participants’ perspectives. To enhance transparency, verbatim quotes have been included to illustrate themes, allowing readers to assess the validity of researchers’ interpretations.

Participants in the SCC arm reported some changes in mental health; however, these were varied and often attributed to external factors. As such, only data from participants in the IC arm were retained. In total, 4 superordinate themes were discerned from the data corpus (Figure 1). Due to their distinct nature and relevance to diverse fields, the research team partitioned the data based on these superordinate themes and conducted separate analyses. This study focuses on the superordinate theme “changes in mental health aspects,” delving into psychological phenomena such as participants’ experiences in modifying illness perceptions over the course. Another superordinate theme, “information seeking,” which addresses online information-seeking behaviors among people living with MS, was reported separately [29]. The remaining 2 themes required quantitative examination to derive their meaning, in alignment with the larger RCT’s goals of quantifying changes in MS symptoms and lifestyle after MSOC completion.

Within “changes in mental-health aspects,” 3 themes relating to illness perceptions were identified. The first theme, “self-efficacy for disease management,” explored perceptions of increased confidence and motivation to manage MS, gained through engaging with and applying lifestyle modification information. Data relating to this theme reflected beliefs about one’s capacity to execute behaviors necessary for disease management, resembling the concept of self-efficacy assessed in the Multiple Sclerosis Self-Efficacy (MSSE) Scale [30], the gold-standard assessment for self-efficacy in persons with MS. Thus, the designation of this theme title was deemed appropriate.

The second theme, “personal control,” explored perceptions of improved sense of personal control over MS, developed through engaging with and applying lifestyle modification information from the IC. Finally, the third theme, “illness coherence,” explored individuals’ experiences of an increased and more coherent cognitive representation of their MS. These 2 themes were named due to the high similarity to the factors “personal control” and “illness coherence,” as described by the Illness Perceptions Questionnaire (IPQ) [31].

Quotations are reported to illustrate themes, identified by the study arm (IC) and participant number.

The theme “self-efficacy for disease management” explored individuals’ perceptions of increased confidence and motivation gained through undertaking the IC, and by commencing the recommended lifestyle changes provided in the IC. Increased self-efficacy had 3 effects, referred to as subthemes, including “taking responsibility over health,” “from contemplation to determination,” and “behavior change in action.”

Participants described improvements in their self-efficacy to manage MS through learning about lifestyle modifications for diet, exercise, and mindfulness practice. Course information appeared to foster motivation to adopt a future-oriented focus and prioritize what changes may be important for improving health, based on evidence presented in the course. Equipped with this lifestyle-modification information, participants described feeling an increased sense of confidence to take up responsibility over their own health and motivation to make recommended lifestyle changes.

Lifestyle modification information increased participants’ sense of responsibility and ownership over managing their health, enhancing their confidence to adopt course recommendations and seek further lifestyle-related information.

Increased confidence and motivation, stemming from engagement, enabled many participants to progress through stages of change in lifestyle management, as delineated by the Stages of Change Model [32]. Improvements in self-efficacy facilitated a shift away from merely contemplating change toward a more determined and committed approach, evident in the development of action plans and intentions to make life-overhauling changes.

Some set specific targets for change, such as supplementing with omega-3 fatty acids, increasing vitamin-D exposure, exercising, and re-engaging with mindfulness techniques including mindful breathing and awareness. For some, this included introducing the first form of intentional exercise in years.

For some, plans had begun to take effect; actions were underway and new patterns of behavior were beginning to form. Participants described improvements in mood and attributed this to the integration of lifestyle changes.

Participant’s responses also raised the possibility of a bidirectional relationship between self-efficacy and change; self-efficacy prompting lifestyle modifications, which may in turn create positive mastery experiences that further enhance self-efficacy.

The theme “personal control” explored individuals’ awareness of their improved personal control over their MS through engaging with lifestyle-related modification information. This theme included 5 subthemes relating to different forms of control, including “control in the face of realism,” “control, in parts,” “control through confidence,” “control over disease course,” and “mending control lost through diagnosis.”

Overwhelmingly, participants expressed an increased sense of control over their MS, although tempered by the realism of the disease. They found a balance between focusing on controllable aspects of MS and accepting that their actions alone may not cure their disease.

Having accepted that MS is a chronic disease, some participants began to focus on the possibility that lifestyle modifications may help to control the progression of symptoms.

Many expressed a conservative view of lifestyle modification, stating that even if modifications may not control the disease or symptoms directly, lifestyle modification provided the opportunity to experience a sense of control.

Participants were prompted to evaluate the utility of all-or-nothing thinking in relation to personal control, that is, the polarity of being “in control” of their MS versus being “out of control” of their MS. Through learning about controllable aspects of health (eg, diet and exercise), participants were able to reconceptualize control as a feeling which varies along a continuum between these 2 possibilities. That is, self-management lifestyle modification offers individuals the opportunity to gain more control over their MS.

The IC made participants feel they could extend their sense of control over their MS and explore other avenues to gain further control of their MS in the future.

For some, confidence was highly interrelated with control, such that increases in confidence coincided with increases in perceptions of personal control.

For 1 newly diagnosed participant, there was a gap between their current reality and a state of perceived control over their MS. However, the IC, and possibly other educational courses, appeared to help them feel more in control.

The theme of “illness coherence” encompassed individuals’ beliefs in a more coherent understanding of MS and included 2 subthemes: “seeking out uncomplicated information” and “small parts make a whole.”

Participants emphasized the challenges associated with complex health information, complicated by medical terminology, and the barrier this imposes for constructing a coherent representation of MS. In contrast, the IC was regarded as a helpful source of information, scaffolding participants’ understanding of health information.

One participant described the protective effects of uncomplicated communication within the acute adjustment period following diagnosis.

The opportunity to understand and piece together complex health information enabled participants to develop a more coherent mental representation of their disease, which they viewed as being important for their general well-being.

This allowed some to begin translating health information into everyday well-being practices, such as mediation, with beneficial results.

This study assessed participants’ responses 1 month after completing the IC of an online, tailored education lifestyle intervention for people living with MS. To the authors’ knowledge, this study is the first to qualitatively explore the impact of lifestyle modification on illness perceptions in a population living with MS. Specifically, it aimed to understand the sequelae of the IC on individuals’ cognitive representations of their MS. Within the superordinate theme of “changes in mental health aspects,” 3 subthemes were identified—“self-efficacy for disease management,” “personal control” perceptions, and “illness coherence” perceptions. Findings contribute to an evidence base on the role of illness perceptions in understanding the experiences of people living with MS. In addition, findings offer preliminary support for the CSM by demonstrating a pathway between exposure to new and valid information and changes in control perceptions, illness coherence, and self-efficacy beliefs [15].

The positive effects of self-managed lifestyle modification on mental health outcomes, such as depression and anxiety, in the population with MS are well established [13]. This study provides evidence that exposure to lifestyle-related information may yield benefits for individuals’ perceptions of their disease. Illness perceptions have been proposed as cognitive mechanisms underlying changes in depression and anxiety [31] and may be helpful in linking lifestyle modification to positive mental health outcomes. Positioned as a valuable adjunct to clinician-administered therapies, lifestyle modification has the potential to empower individuals to assume greater responsibility over their disease management, thereby enhancing the comprehensiveness of the treatment approach.

Gaining a sense of control, which is commonly reduced following MS diagnosis [33], was a primary motivating factor for engaging with the MSOC, as identified in an earlier qualitative study nested within a pilot feasibility study of the MSOC [34]. Furthermore, evidence substantiates the importance of personal control perceptions for mental health outcomes in people living with MS (eg, Brown et al [35] and Jopson and Moss-Morris [36]). While the current analysis confirms the importance of personal control perceptions and the impact of the IC on this aspect, it also offers novel insights into the multidimensional nature of personal control perceptions in MS. Findings illustrate how personal control may be formed, the extent of control gained, and its relevance across MS-related experiences.

Participants’ reports suggested a link between control perceptions and confidence, with each potentially influencing the other. Gaining more information about lifestyle modification, helped to bolster individuals’ confidence and enabled them to feel more in control of MS. Importantly, this was tendered by a pragmatic, continuum-based view of control over MS. While some participants described retrospective feelings of helplessness and a lack of control at the time of diagnosis, they acknowledged the possibility of exerting partial control over MS, aided through their engagement with the IC. This is unexpected as most study participants were within the first 5 years of diagnosis, a period marked by increased distress and tendencies toward all-or-nothing cognitive patterns [37]. Notably, most participants in this analysis scored within the normal ranges for depression and anxiety, contrasting findings from previous observational research [2]. This suggests that the current sample may represent a subgroup of people living with MS who have more positive mental health and may face fewer barriers to lifestyle modification. Considering that motivation difficulties and fatigue—hallmark symptoms of depression [38,39]—are known barriers to lifestyle modification [40], future research should explore how mental health influences engagement with lifestyle modification information, the initiation of lifestyle changes, and the extent to which mental health may impact the effectiveness of self-management interventions on personal control perceptions.

Participants’ responses in the current study highlighted the changing nature of illness coherence perceptions, triggered by an MS diagnosis, and shaped through their interaction with the IC. One participant described their experience of diagnosis as a sudden shift, “catapulting” them into a situation that required them to reconstruct their identity in midlife. Notably, given that MS is frequently misunderstood and concealed, the period following diagnosis often requires individuals to assert their understanding of MS and how MS uniquely manifests within them [41]. Therefore, sourcing health information represents a high priority for people living with MS [41,42].

The concept of illness coherence represents a relatively new idea, distinct from the construct of “sense of coherence,” which enables individuals to cope with adverse experiences and is regarded as a dispositional trait (ie, a characteristic embedded within the personality) [42]. Sense of coherence has demonstrated predictive power across a spectrum of physical and mental health outcomes in people living with MS [43,44]; however, given its supposed trait-like structure, its amenability to intervention may be limited. In contrast, illness coherence perceptions have been shown to exhibit temporal variability [45], and their connections to mental health outcomes, encompassing depression and anxiety, have been documented in a handful of MS studies (eg, Kroencke et al [46] and Lynch et al [47]) and are firmly established within the context of other chronic disease populations [48].

The CSM posits that exposure to new and expert information may alter illness perceptions, including psychological adjustment outcomes [15]. The present study extends this concept, suggesting a precondition for such change—health information must be presented in a way that can be easily understood by individuals without specialized medical knowledge. Participant responses suggested that their engagement with uncomplicated health information within the IC facilitated a process of reintegration, helping them to “put things together” again, toward a coherent mental representation of MS. Consequently, participants described improvements in well-being and the practical application of information provided in the IC into daily life, including mindfulness.

Individuals reported increased self-efficacy for disease management following engagement with the IC which manifested in diverse ways. The Stages of Change Model [32] is a highly influential framework for understanding health-related behavior, and its application can lend meaning to the present findings. Through this lens, participant responses can be allocated to 2 different stages of readiness. The first set of responses suggested that the IC helped them overcome ambivalence toward change, progressing from Prochaska and Velicer’s [32] “contemplation stage to preparation or determination” [32]. At this stage, individuals had established the belief that lifestyle modification may lead to a healthier life and described planning steps toward change, with some already experiencing positive effects.

The second set of responses suggested a more advanced stage of change, narrating experiences consistent with a transition from “preparation/determination” into “action.” By incorporating recommended adjustments, including increasing exercise, mindfulness practices, and making dietary modifications, participants noted improvements in their well-being, within a mere month, further enhancing their self-efficacy. These responses raise the possibility of a bidirectional relationship between self-efficacy and lifestyle modification changes, whereby changes in 1 factor feed into changes in the other. The pathway from self-efficacy to behavior change has been tested and substantiated in previous research [49], although operating under the assumption that changes in self-efficacy precede behavioral changes.

It should be noted that an individual’s baseline stage of change (ie, where individuals are at in terms of contemplating or actioning change) may predict the likelihood of behavior change [50]. The act of enrolling in and completing a self-guided lifestyle modification course likely signifies contemplation of change. Future research may consider assessing individuals’ baseline self-efficacy for disease management as one index of readiness for change. Tailoring lifestyle modification educational programs according to the individual’s stage of readiness may help to optimize lifestyle modification change. This approach may also help cater to those who are less inclined to engage with lifestyle modification (eg, in the precontemplation stage), as well as those focused on maintaining changes and preventing regression to earlier stages.