Measurement of Anxiety by Forearm Blood Flow

¹ Senior Registrar, Department of Psychological Medicine, St. Thomas's Hospital, London S.E.1

1. The study was designed to examine the use of forearm blood flow as an objective index of anxiety. Forty normal controls and 40 mixed neurotics were compared with 20 patients with chronic anxiety states, and measurements of forearm blood flow, heart rate and blood pressure were made during "basal" (resting) and "stress" conditions.

2. The results met three criteria of validity.

(a) In the controls, moderate anxiety induced by stressful mental arithmetic produced a mean increase in forearm blood flow measured by venous occlusion plethysmography of 334 per cent.

(b) The chronic anxiety state patients had a mean "basal" forearm blood flow (4.8 ml./100 ml./min.) which was more than twice as great as that of the mixed neurotics (2.3) and normal controls (2.2).

(c) The three groups were placed in the same order by the Taylor Scale of Manifest Anxiety and an anxiety self-rating scale.

3. The test-retest reliability of "basal" forearm blood flow was high in 20 subjects in whom the level of anxiety remained unaltered.

4. Diminution in anxiety of six chronic anxiety state patients and six post-leucotomy patients was associated with a significant decrease in "basal" forearm blood flow.

5. It is concluded that "basal" forearm blood flow is a valid and reliable index of anxiety which can be of diagnostic value. It is also suitable for objectively assessing drug treatment, psychotherapy, behaviour therapy or modified leucotomy.

6. A physiological concept of anxiety as defence reaction arousal is presented.