Letters to the Editor
Breath-Holding in Anxiety Disorders
Dear Editor:
The breath-hold test may be a simple and natural method of inducing endogenous CO2 increase. We aimed to observe whether anxiety disorder patients (diagnosed according to DSM-IV criteria) respond in a similar way to the induction of panic attacks by a breath-holding test.
We randomly selected 29 panic disorder (PD) patients (18 women and 11 men; mean age 36.8 years, SD 9.6), 27 social anxiety disorder (SAD) patients (15 women and 12 men; mean age 42.8 years, SD 11.3), 21 generalized anxiety disorder (GAD) patients (14 women and 7 men; mean age 35.3 years, SD 15.0), and 23 comorbid anxiety disorder (CAD) patients (14 women and 9 men; mean age 37.5 years, SD 8.9) in the Laboratory of Panic and Respiration, Rio de Janeiro, Brazil. Our comparison group comprised 30 subjects with no family history of anxiety or mood disorder (18 women and 12 men; mean age 33.7 years, SD 13.8 years). We obtained written informed consent, and our local ethics committee approved the protocol. The inclusion criteria were as follows: age 18 to 55 years, occurrence of at least 3 panic attacks in the previous 2 weeks for PD patients, and a negative urine test for medications. Exclusion criteria were unstable medical condition, cognitive- behavioural psychotherapy during the study, and use of any psychotropic medication for 5 weeks.
To measure the baseline anxiety level, we asked subjects to complete (before and after the test) the Subjective Units of Disturbance Scale (SUDS) (1) and the Diagnostic Symptom Questionnaire (DSQ) (1) adapted for DSM-IV. Based on the DSQ, we defined a panic attack as 1) 4 or more symptoms of a panic attack according to DSM-IV criteria; 2) at least one of the cognitive symptoms; 3) feelings of panic or fear, similar to spontaneous panic attacks; and 4) the agreement of 2 diagnosis-blinded raters at clinical diagnosis evaluation.
The breath-holding test comprised 4 trials as used by Van der Does (2). The panic rates assigned showed that significantly more PD patients had a panic attack in response to breath-holding: 44.8% (n = 13) of PD patients, 14.8% (n = 4) of SAD patients, 9.5% (n = 2) of GAD patients, 13.0% (n = 3) of CAD patients, and 4.0% (n = 1) of control subjects had a panic attack after the test (c² = 23.67, df 4, P = 0.001). There was no significant sex difference in any group (c² = 0.64, df 4, P = 0.958).
Although the SUDS results showed that PD patients tended to be more sensitive than other groups, all groups showed increased anxiety levels after the test. There were no statistical difference among the groups (2-way analysis of variance [ANOVA], group-by-time interaction: F4,125 = 1.283, P = 0.238).
Our main finding is the clear differentiation of PD patients from other anxiety disorder patients by a simple respiratory test. The precise criteria for induced panic attack may be the crucial point for our results. The data support Klein’s theory (3) and suggest that there is an association between PD and panic attacks in this breath-holding test. In respect to the induction of panic attacks, other anxiety disorders—SAD, GAD, and CAD—may be differentiated from PD by this respiratory test.
References
1. Bech P, Kastrup M, Rafaelsen OJ. Mini-compendium of rating scales for states of anxiety, depression, mania, schizophrenia with corresponding DSM III syndromes. Acta Psychiatr Scand 1986:73:1–37.
2. Van der Does AJW. Voluntary breath holding: not a suitable probe of the suffocation alarm in PD. Behav Res Ther 1997;35:779–84.
3. Klein DF. False suffocation alarms, spontaneous panics, and related conditions. An integrative hypothesis. Arch Gen Psychiatry 1993;50:306–17.
Antonio E Nardi, MD, PhD
Alexandre M Valença, MD, PhD
Fabiana L Lopes, MD
Isabella Nascimento, MD MSc
Marco A Mezzasalma, MD
Walter A Zin, MD, PhD
Rio de Janeiro, Brazil
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