A large longitudinal cohort study out of Denmark, recently published in the American Journal of Psychiatry, corroborates previous evidence that antipsychotics increase the risk of developing diabetes in people diagnosed with schizophrenia.
Numerous medications have been associated with elevated risk of diabetes. Antidepressants, for example, are understood to reduce pancreatic insulin secretion, which is believed to increase the risk of developing diabetes. This elevated risk has also been demonstrated in children and youth exposed to antipsychotics.
The authors of the present study point out that the prevalence of diabetes mellitus is 4-5 times higher in people diagnosed with schizophrenia. Similar to the theory surrounding antidepressants, it is believed that impaired glucose tolerance and increased insulin resistance can explain some of the elevated rates of diabetes within individuals diagnosed with schizophrenia who are prescribed antipsychotics. Moreover, abnormal glucose tolerance has been shown to be more prevalent among individuals diagnosed with schizophrenia than those without.
This latest study was conducted by pulling data form the Danish Civil Registration System for people born on or after January 1977 and followed up until January 2013. Information on diabetes diagnosis was pulled from the Danish National Patient Register and the Danish National Registry. Information on medication for diabetes was extracted from the Danish National Prescription Registry. Data regarding schizophrenia diagnosis was gathered from the Danish Psychiatric Central Research Register, while information on antipsychotic prescriptions was pulled from the Danish National Prescription Registry. Possible covariates including gender, urbanicity, calendar period, and family history of diabetes were also collected.
A total of 2,736,510 people were followed for a total of 49,582,279 person-years. Within this, 8,945 (.33%) of people were diagnosed with schizophrenia. Individuals with this diagnosis were significantly more likely to have a family history of diabetes. Within this cohort, 14, 118 (.52%) people developed diabetes.
Of those who were not exposed to any antipsychotics, 12,976 (.5%) without a schizophrenia diagnosis and 11 (.9%) with this diagnosis developed diabetes. After adjusting for potential confounders, the risk was elevated threefold compared to those without a schizophrenia diagnosis.
Within those diagnosed, 4, 623 (51.7%) were prescribed antipsychotics. When prescribed antipsychotics, rate of diabetes more than three times greater than rates before receiving antipsychotics. No differences were observed between first-generation and second-generation antipsychotics.
This large nationwide study confirmed endogenous risk for diabetes among individuals diagnosed with schizophrenia, with risks increasing significantly when antipsychotics are prescribed. Moreover, the threefold risk identified in this present study matches the threefold elevated risk found in children and youth exposed to antipsychotics.
Rajkumar, A. P., Horsdal, H. T., Wimberley, T., Cohen, D., Mors, O., Børglum, A. D., & Gasse, C. (2017). Endogenous and antipsychotic-related risks for diabetes mellitus in young people with schizophrenia: a Danish population-based cohort study. American Journal of Psychiatry, appi-ajp. (Link)