We explored the question of whether generalised anxiety is mainly defined by individual personality characteristics or by contextual influences. To that end, we analysed data obtained by a sample of 150 healthy volunteers subjected to a series of 7.5% and placebo inhalations. The participants completed the Eysenck Personality Questionnaire and the Generalised Anxiety Disorder Inventory (GADI), a new tool that has shown good reliability, convergent and divergent validity in the measurement of generalised anxiety, and comprises three factors relating to cognitive, somatic and sleep symproms of GAD (Argyropoulos et al, 2007, J Psychopharmacology, 21: 145-152). We found that the neuroticism trait was associated with all three factors of the GADI, anxiety & worry (r=0.59), sleep problems (r=0.29) as well as somatic symptoms (r= 0.33), and the total GADI score (r=0.59). We concluded that GAD, as quantified by the GADI, is partly a stable trait, but there remains substantial variation that cannot be explained by personality alone.