Association between corneal temperature and mental status of treatment-resistant schizophrenia inpatients

Introduction: Preliminary point-prevalent data suggest that drug-free schizophrenia patients may exhibit increased body/corneal temperature, that antipsychotic drugs (APDs) may decrease body/core temperature and that patients' mental status might be associated with their body/corneal temperature. Hence, we hypothesized that treatment-resistant psychotic APD-treated schizophrenia patients' mental status may correlate with their corneal temperature during a continuous 6-week period. Methods: Corneal temperature of 12 treatment-resistant schizophrenia inpatients and 16 healthy volunteers was evaluated 2-3 times a week during 6 consecutive weeks using a flir thermal imaging camera. Results: A significant and substantial correlation was found between inpatients' mean weekly Positive and Negative Syndrome Scale (PANSS)'s total scores and their mean weekly corneal temperature during the 6-week study period (r = 0.82; n = 6 weeks; p = 0.043). There was no significant difference in mean 6-week corneal temperature between the patient group and the healthy subjects (34.25 ± 0.64 °C vs. 34.39 ± 0.69 °C, respectively; t = 1.127, df = 131, p = 0.26). Conclusions: This study indicates that treatment-resistant overtly psychotic schizophrenia inpatients' mental status (as assessed by the PANSS) correlates with their corneal temperature. The relevance of these phenomena to the pathophysiology of schizophrenia, the biological mechanism underlying corneal temperature alterations and the possible role of temperature-modulating drugs (neuroleptics or non-neuroleptics) on schizophrenic psychosis merits further large-scale investigation in both medicated- and drug-free schizophrenia patients compared to matched controls.