Background/Objectives: Intentional insulin omission (IIO), commonly referred to as diabulimia, is a high-risk behavioural phenomenon observed mainly in adolescents and young adults with type 1 diabetes mellitus (T1D). Defined as the deliberate reduction or omission of insulin to influence body weight, IIO lies at the intersection of metabolic management and eating disorder psychopathology. Despite serious health risks, including diabetic ketoacidosis, microvascular complications, and increased mortality, it remains under-recognised due to stigma, diagnostic ambiguity, and overlap with routine diabetes self-management. This review aimed to examine the prevalence, psychological mechanisms, and clinical consequences of IIO. Methods: On 1 April 2026, we conducted a systematic search of PubMed, Scopus, APA PsycInfo/PsycArticles and Cinahl for studies investigating intentional insulin omission and related metabolic and psychological outcomes in T1D. Clinical and epidemiological studies assessing prevalence, risk factors, and interventions were included. Results: Twenty-nine studies met the inclusion criteria. Prevalence estimates ranged from 20% to 45%, with higher risk among females, adolescents, and individuals experiencing diabetes-related distress or body dissatisfaction. Psychological factors—including fear of weight gain, emotion dysregulation, depressive symptoms, and identity conflicts—were associated with IIO onset and maintenance. IIO was consistently linked to poor glycaemic control, elevated HbA1c levels, and adverse metabolic and psychological outcomes. Screening tools such as the Diabetes Eating Problem Survey–Revised (DEPS-R) may support early identification, while effective management requires integrated multidisciplinary care. Conclusions: Although IIO is not formally classified as an eating disorder in current diagnostic systems, it shares important psychopathological features with eating disorders and may represent a diabetes-specific disordered eating behaviour with life-threatening consequences.
Anesini et al. (Mon,) studied this question.