The effect of anxiety on postural control in humans depends on visual information processing.

To examine the possibility that anxiety affects the control of postural balance, state anxiety, and body sway during orthostatic standing were measured twice in college students with an interval of 1 month. Correlations between the changes in state anxiety and the parameters of body sway were examined by Pearson's correlation analysis. The changes in the enveloped area of body sway and in the maximum length of the antero-posterior body sway showed a positive correlation with the changes in state anxiety (r = 0.543 and 0.659, respectively). The data showed that an increase in anxiety caused instability in the control of postural balance. These correlations were abolished when the eyes were closed. In conclusion, anxiety affects the processing of visual input and influences the net performance of postural control. Copyright 2004 Elsevier Ireland Ltd.