Preference for caffeine appears earlier in non-anxious than in anxious mice

Caffeine has reinforcing and anxiogenic properties. We have investigated whether the anxiety level of mice may influence their caffeine consumption. In a population of CD1 mice, animals were selected as anxious and non-anxious, using the elevated plus maze and the light/dark box tests. After a period during which we made mice able to associate the central effect of caffeine with the pipette delivering this substance, animals had free access to solvent (solution of sodium benzoate) and one of caffeine (0.3g/l) dissolved in this solvent. A progressive preference for the caffeine solution developed in both groups, but this occurred later in anxious than in non-anxious mice. Thus, it appears that the preference for caffeine is delayed in the anxious animals.