Anxiety process “theta” biomarker in the stop signal task eliminated by a preceding relaxation test

Anxiety disorders are currently the most prevalent psychiatric diseases in Europe and the United States, the 6th highest cause of years of life lived with disability, and so a grave and ever-increasing burden on health care resources. Categorization of specific anxiety disorders is constantly evolving, but even the new Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM–5) manual uses symptom lists, not objective biomarkers. The DSM–5 and International Classification of Diseases (10th ed.) also aim for single diagnoses, but patients present with mixed symptoms that fit multiple diagnoses. In 1 step toward a solution to this problem, we previously reported on a human electroencephalogram anxiety process biomarker, goal-conflict-specific rhythmicity (GCSR) in a stop signal task (SST). GCSR appears homologous with rodent rhythmical slow activity, 4–12 Hz “theta” rhythmicity that, in the rat hippocampus, predicts human clinical anxiolytic action with, so far, no false positives (even with sedatives) or negatives (even with drugs ineffective in panic or depression). However, within-task stability of GCSR is too variable for test−retest. Here we tested the stability of GCSR when a simple relaxation task preceded the SST. We found that prior exposure of participants (56 female, 39 male; mean age = 21.87 years; reporting no medical or psychological treatment or any type of emotional disorder in the last 12 months) to the relaxation task appeared to almost completely eliminate GCSR. We therefore conclude that, when elicited in the stop signal task, GCSR represents a labile emotional state and should be assessed alone or as the 1st test of a series.