1. Basal plasma and spinal fluid noradrenaline were increased in patients with primary hypertension and phaeochromocytoma compared with normotensive patients (P < 0.01).
2. Patients with primary hypertension had more anger (P < 0.01), anxiety (P < 0.01) and guilt (P < 0.05) than normotensive patients or patients with phaeochromocytoma.
3. The responses of noradrenaline and adrenaline concentrations were similar after mental and isometric stress in primary hypertensive and normotensive subjects.
4. However, after mental stress and isometric exercise there were increased responses of plasma noradrenaline and systolic blood pressure respectively, in patients with high anxiety and anger compared with those below the 50th percentile (P < 0.05).
5. Increased central and peripheral neurogenic tone at rest and after stress in association with increased anxiety and suppressed anger appear to be pathogenic factors in some patients with primary hypertension and may not be a result of the blood pressure elevation.