Anxiety is common among individuals with asthma, and the relationship between asthma symptoms and anxiety can be challenging. Existing treatments for comorbid anxiety and asthma are limited. Hyperventilation, a shared feature of both conditions, negatively impacts lung function and symptoms of asthma and anxiety.
A clinical trial investigated whether a treatment targeting hyperventilation could improve anxiety in asthma patients with high anxiety levels. One hundred and twenty adult patients with asthma, who spoke English or Spanish, were randomly assigned to receive either Capnometry-Assisted Respiratory Training (CART) aimed at raising Pco2 levels or feedback to slow respiratory rate (SLOW). While anxiety was not a specific inclusion criterion, 21.7% of participants had clinically significant anxiety levels based on the Hospital Anxiety and Depression Scale (HADS). Anxiety, depression, sensitivity, and negative affect were assessed at baseline, post-treatment, 1-month follow-up, and 6-month follow-up.
Asthma patients with high baseline anxiety experienced greater reductions in anxiety sensitivity and negative affect in the CART group compared to the SLOW group. Moreover, at the 6-month follow-up, these patients showed lower anxiety sensitivity, negative affect, and depression scores in the CART group compared to the SLOW group. Patients with low baseline anxiety did not exhibit significant differences in outcomes between the CART and SLOW groups.
Among asthma patients with high anxiety levels, the brief training aimed at raising Pco2 levels resulted in significant and sustained reductions in anxiety sensitivity and negative affect compared to slow-breathing training. These findings support using Pco2 as a potential physiological target for reducing anxiety in asthma patients. By addressing hyperventilation, this treatment approach may offer new possibilities for managing anxiety in individuals with asthma.