The influence of alcohol oral intake on the effects of 35% CO2 challenge. A study in healthy volunteers.

OBJECTIVE

Alcohol use disorders and panic disorder co-occur at a rate that exceeds chance significantly. The underlying mechanism of alcoholism associated with anxiety has rarely been examined using experimental methodologies. The present study in healthy volunteers tested whether alcohol consumption reduces anxiety associated with a panic-challenge procedure (35% CO2 challenge).

METHODS

The study design was placebo-controlled, double-blind, randomized. Eight healthy volunteers were enrolled; all subjects had an alcohol and a placebo oral intake according to a crossover design. After each consumption the subjects underwent the 35% CO2 challenge and a series of anxiety symptom assessments.

RESULTS

After the alcohol intake, the subjects presented a significant reduction in the anxiety state associated with the challenge procedure. The Panic Symptom List score is significantly lower after alcohol intake (P = 0.032), as compared with the placebo, and the Visual Analogue Anxiety Scale shows a trend to be lower after alcohol intake (P = 0.111).

CONCLUSIONS

Moderate doses of alcohol acutely decrease the response to a 35% CO2 challenge in healthy volunteers. These results lend support to the pharmacological anxiolytic effect of alcohol and suggest that this property may reinforce the drinking behaviour among those with high levels of anxiety.