Association of insulin-manipulation and psychiatric disorders: A systematic epidemiological evaluation of adolescents with type 1 diabetes in Austria.

Background/Objective The aim of this study was to systematically assess the association of insulin-manipulation (intentional under- and/or overdosing of insulin), psychiatric comorbidity and diabetes complications. Methods Two diagnostic interviews (Diabetes-Self-Management-Patient-Interview and Children's-Diagnostic-Interview for Psychiatric Disorders) were conducted with 241 patients (age 10-22) with type 1 diabetes (T1D) from 21 randomly selected Austrian diabetes care centers. Medical data was derived from medical records. Results Psychiatric comorbidity was found in nearly half of the patients with insulin-manipulation (46.3%) compared to a rate of 17.5% in patients, adherent to the prescribed insulin therapy. Depression (18.3% vs 4.9%), specific phobia (21.1% vs 2.9%), social phobia (7.0% vs 0%), and eating disorders (12.7% vs 1.9%) were elevated in patients with insulin-manipulation. Females (37.7%) were more often diagnosed (P = 0.001) with psychiatric disorders than males (18.4%). In females, the percentage of psychiatric comorbidity significantly increased with the level of non-adherence to insulin therapy. Insulin-manipulation had an effect of +0.89% in HbA1c (P = <0.001) compared to patients adherent to insulin therapy, while there was no association of psychiatric comorbidity with metabolic control (HbA1c 8.16% vs 8.12% [65.68 vs 65.25 mmol/mol]). Ketoacidosis, severe hypoglycemia, and frequency of outpatient visits in a diabetes center were highest in patients with insulin-manipulation. Conclusions This is the first study using a systematic approach to assess the prevalence of psychiatric disorders in patients who do or do not manipulate insulin in terms of intentional under- and/or overdosing. Internalizing psychiatric disorders were associated with insulin-manipulation, especially in female patients and insulin-manipulation was associated with deteriorated metabolic control and diabetes complications.