Sixty-two patients with persistent NUD symptoms were compared with healthy persons of comparable age, sex and social status on a variety of life stress, personality, mood state and coping measures. Highly threatening chronic difficulties were significantly more evident in the NUD group than controls (98 and 2% respectively), as were acute life events which remained highly threatening one week after their onset. Other psychological variables significantly related to NUD were high levels of anxiety and depressive symptoms, personality traits indicating neurotic or anxious tendencies, a tendency to use less mature stress-coping mechanisms and to have less high-quality emotional support. Multivariate analysis revealed the presence of highly threatening stressors to be by far the most important predictor of NUD status. The implications of these findings in relation to the significance of stress and other psychological variables in the aetiology and treatment of NUD are discussed.