Illness identity and adjusting to type I diabetes: A four-wave longitudinal study.

Objectives: Prior research has linked illness identity-or the extent to which the illness is integrated into one's identity-to diabetes-specific functioning. Four illness identity dimensions have been identified: rejection, acceptance, engulfment, and enrichment. As longitudinal research on this topic is scarce, this study examined developmental trajectories of illness identity and prospective associations between illness identity and diabetes-specific functioning.

Method: Adolescents and emerging adults with Type I diabetes, aged 14 to 25 (M = 19; 54% girls), participated in a four-wave longitudinal study spanning 3 years (N = 559 at Time 1). Participants filled out questionnaires on illness identity, treatment adherence, and diabetes-specific distress. Hemoglobin A (HbA) values were obtained from participants' medical records. To chart the development of illness identity over time, we performed latent growth curve modeling. Cross-lagged analysis was used to examine prospective associations between illness identity and diabetes-specific functioning.

Results: We observed small linear increases in acceptance (M = .05, p < .01) and engulfment (M = .03, p < .05) and a small linear decrease in rejection (M = -.08, p < .001) across waves (with scale scores ranging between 1 and 5). Rejection negatively predicted and enrichment positively predicted treatment adherence 1 year later, which, in turn, positively predicted enrichment and negatively predicted engulfment over time. Furthermore, rejection and engulfment positively predicted diabetes-specific distress 1 year later. Finally, diabetes-specific distress and HbA1c positively predicted engulfment 1 year later. Standardized cross-lagged coefficients ranged between |.05| and |.11|.

Conclusions: We identified small but interesting changes in three out of four illness identity dimensions. Prospective associations between illness identity and diabetes-specific functioning were bidirectional in nature. (PsycInfo Database Record (c) 2021 APA, all rights reserved).