THE MUSCLES respond to voluntary control and yet, during immobility, are known to reflect levels of autonomic arousal.^1,2 But since muscle tension levels do not agree fully with other indices of arousal,³ the question arises as to what variables other than arousal are expressed in the level of muscle tension. Balshan⁴ found that the trait of anxiety was not related to muscle tension levels at rest but that it was related to the amount of increase in muscle tension when a normal subject was aroused by white noise. After demonstrating that this same principle applies to psychiatric patients, Goldstein⁵ went on to show that, when trait anxiety is kept constant, both depression and psychosis in a psychiatric patient are associated with a greater muscular response to white noise. Suspecting that the muscle tension increase is not just a component of the anxiety response but is