Suicide and attempted suicide by insulin: A systematic review

Background: Intentional insulin overdose either in people with diabetes or without can be used to attempt suicide. Massive insulin administration may result in coma and unexplained hypoglycemia. In this study, we aim at reviewing the demographic data of suicidal cases, the relation of psychiatric illness to dying by suicide and attempting suicide using insulin, route of insulin administration and outcome, post-mortem findings in suicide by insulin and collaborative evidence, initial presentation, blood glucose level and complications in attempting suicide cases. Methods: PubMed, Web of Science, and Scopus databases were searched on October 4, 2021, using a comprehensive strategy review. The following search terms were applied: (Insulin) AND (toxicity OR overdose OR toxicology OR poisoning OR intoxication) AND (Suicide OR attempted suicide OR Self-harm OR Self harm). The search strategy was set based on PRISMA guideline; 11 papers were eligible for inclusion and additional 23 studies were added from the citation search. All English articles related to suicide and attempted suicide using insulin were included and no specific timeline or filter was used. Any non-English article and accidental or homicidal cases were excluded from the review. Results: The analysis included 179 victims, aged between 13 to 76 years with male predominance and people with diabetes, especially T1DM, having higher prevalence, with subcutaneous injection being the most common route of administration. In addition, psychiatric illnesses and multiple suicide attempts were identified in many cases besides the use of insulin in a combination with other medications. Conclusions: Dying by suicide using insulin is uncommon, however, as diabetes mellitus prevalence increases worldwide, it is expected that intentional insulin overdose will also increase. Furthermore, psychiatric illnesses and easy access to insulin are important factors that should be put into consideration.