title: Low pre-treatment end-tidal CO2predicts dropout from cognitive-behavioral therapy for anxiety and related disorders.
abstract: Recent clinical trial research suggests that baseline low end-tidal CO2(ETCO2, the biological marker of hyperventilation) may predict poorer response to cognitive-behavioral therapy (CBT) for anxiety-related disorders. The present study examined the predictive value of baseline ETCO2among patients treated for such disorders in a naturalistic clinical setting. Sixty-nine adults with a primary diagnosis of a DSM-5 anxiety disorder, obsessive-compulsive disorder, or posttraumatic stress disorder completed a 4-min assessment of resting ETCO2, and respiration rate (the first minute was analyzed). Lower ETCO2was not associated with a diagnosis of panic disorder, and was associated with lower subjective distress ratings on certain measures. Baseline ETCO2significantly predicted treatment dropout: those meeting cutoff criteria for hypocapnia were more than twice as likely to drop out of treatment, and ETCO2significantly predicted dropout beyond other pre-treatment variables. Weekly measurement suggested that the lower-ETCO2patients who dropped out were not responding well to treatment prior to dropout. The present results, along with previous clinical trial data, suggest that lower pre-treatment ETCO2is a negative prognostic indicator for CBT for anxiety-related disorders. It is suggested that patients with lower ETCO2might benefit from additional intervention that targets respiratory abnormality.
authors.affiliation: The Institute of Living, United States; Yale University School of Medicine, United States. Electronic address: david.tolin@hhchealth.org.
authors.forename: David F
authors.initials: DF
authors.lastname: Tolin
authors.affiliation: The Institute of Living, United States.
authors.forename: Amber L
authors.initials: AL
authors.lastname: Billingsley
authors.affiliation: The Institute of Living, United States.
authors.forename: Lauren S
authors.initials: LS
authors.lastname: Hallion
authors.affiliation: The Institute of Living, United States; Yale University School of Medicine, United States.
authors.forename: Gretchen J
authors.initials: GJ
authors.lastname: Diefenbach
mesh_terms: D000328:Adult; D001008:Anxiety Disorders / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy; D001944:Breath Tests; D002245:Carbon Dioxide / Q000378:metabolism*; D015928:Cognitive Behavioral Therapy; D005260:Female; D006801:Humans; D006985:Hyperventilation / Q000378:metabolism / Q000523:psychology*; D016857:Hypocapnia / Q000150:complications / Q000523:psychology*; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy; D010352:Patient Dropouts; D056152:Respiratory Rate / Q000502:physiology; D013313:Stress Disorders, Post-Traumatic / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy; D013315:Stress, Psychological / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology / Q000523:psychology; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide
keywords: Anxiety disorders; Attrition; CO(2); Dropout; Hyperventilation; Hypocapnia; Obsessive-compulsive disorder