Abstract
BACKGROUND: Recurrence is a problem for many patients who have episodes of depression. In experimental settings, hyporeactivity in the Electrodermal Orienting Reactivity (EDOR) test has been observed to be more frequent in these patients. The aim of this study was to investigate the clinical value of this test with regard to a prognosis of episode recurrence in patients hospitalized for depression. METHODS: The study was performed using a cohort design at a specialized psychiatric clinic in Warsaw, Poland. The primary endpoint measure was relapse or recurrence of depression. Data on electrodermal reactivity measured by the EDOR test, clinical status, and psychiatric history were collected at the clinic. Relapse and recurrence data were collected by clinical interviews 1 year after the EDOR test. The predictive (adjusting for confounders) and comparative (relative to other predictors) performance of electrodermal hyporeactivity was assessed using simple and multiple binary logistic regression. RESULTS: The patient sample included 97 patients aged between 20 and 81 years (mean, 51.2 years). Twenty patients (20.6%) were hyporeactive in the EDOR test. The group of hyporeactive patients did not differ significantly from the reactive group with regard to background factors or clinical status on admission. Forty-seven patients (51.6%) had at least one depressive episode during the follow-up period. In the analysis including potential confounders, the likelihood of relapse or recurrence of depression was nearly five times higher among the hyporeactive patients than the reactive patients (odds ratio [OR], 4.7; 95% confidence interval (CI), 1.3-16.2; p = 0.015). In the comparative analysis, only hyporeactivity was found to be associated with recurring episodes (OR, 3.3; 95% CI, 1.1-10.2; p = 0.036). CONCLUSIONS: Electrodermal hyporeactivity was associated with a higher risk of relapse or recurrence after discharge among patients hospitalized for depression. This finding warrants further clinical investigations that cover different types of depression and account for causal mechanisms. TRIAL REGISTRATION: The study design was registered in the German Clinical Trials Register ( DRKS00010082 ).