Inhalation of 7.5% carbon dioxide (CO2) increases anxiety and autonomic arousal and provides a novel experimental model of anxiety with which to evaluate pharmacological and psychological treatments for anxiety. To date several psychotropic drugs have been evaluated using the 7.5% CO2 model, including benzodiazepines, selective serotonin reuptake inhibitors (SSRIs) and serotonin noradrenaline reuptake inhibitors (SNRIs); however, it has yet to be used to evaluate psychological interventions. We compared the effects of two core psychological components of mindfulness-meditation (open monitoring, OM and focused attention, FA) against general relaxation, on subjective, autonomic and neuropsychological outcomes in the 7.5% CO2 experimental model.32 healthy screened adults were randomized to complete 10 minutes of guided open monitoring, focused attention or relaxation, immediately before inhaling 7.5% CO2 for 20 minutes. During CO2-challenge participants completed an eye-tracking measure of attention control and selective attention. Measures of subjective anxiety, blood pressure and heart rate were taken at baseline and immediately following intervention and CO2-challenge.OM and FA practice reduced subjective feelings of anxiety during 20-minute inhalation of 7.5% CO2 compared to relaxation control. OM practice produced a strong anxiolytic effect, whereas the effect of FA was more modest. Anxiolytic OM and FA effects occurred in the absence of group differences in autonomic arousal and eye-movement measures of attention. Our findings are consistent with neuropsychological models of mindfulness-meditation that propose OM and FA activate prefrontal mechanisms that support emotion regulation during periods of anxiety and physiological hyper-arousal. Our findings complement those from pharmacological treatment studies, further supporting the use of CO2 challenge to evaluate future therapeutic interventions for anxiety.
- Experimental Medicine
Ainsworth, B., Marshall, J. E., Meron, D., Baldwin, D. S., Chadwick, P., Munafo, M. R., & Garner, M. (2015). Evaluating psychological interventions in a novel experimental human model of anxiety. Journal of Psychiatric Research, 63, 117-122. https://doi.org/10.1016/j.jpsychires.2015.02.001