Abnormal glycemic homeostasis at the onset of serious mental illnesses: A common pathway

Abstract

Objective: Patients with serious mental illnesses exhibit a reduced lifespan compared with the general population, a finding that can not solely rely on high suicide risk, low access to medical care and unhealthy lifestyle. The main causes of death are medical related pathologies such as type 2 diabetes mellitus and cardiovascular disease; however pharmacological treatment might play a role.

Material and methods: We compared a two hour glucose load in naïve patients at the onset of a serious mental illness (N=102) (84 patients with a first episode of schizophrenia and related disorders, 6 with a first episode of bipolar I disorder and 12 with a first episode of major depression disorder) with another psychiatric diagnose, adjustment disorder (N=17) and matched controls (N=98).

Results: Young patients with serious mental illness showed an increased two hour glucose load compared with adjustment disorder and the control group. Mean two hour glucose values [±standard deviation] were: for schizophrenia and related disorders 106.51mg/dL [±32.0], for bipolar disorder 118.33mg/dL [±34.3], for major depressive disorder 107.42mg/dL [±34.5], for adjustment disorder 79.06mg/dL[±24.4] and for the control group 82.11mg/dL [±23.3] (p<0.001).

Conclusions: Our results reflect an abnormal metabolic pathway at the onset of the disease before any pharmacological treatment or other confounding factors might have taken place. Our results suggest a similar glycemic pathway in serious mental illnesses and the subsequent need of primary and secondary prevention strategies.

Keywords: Bipolar disorder; Major depressive disorder; Mortality; Schizophrenia; Thrifty psychiatric phenotype; Type 2 diabetes mellitus.