Cigarette smoking and panic. A critical review of the literature

OBJECTIVE: Cigarette smoking increases the risk of panic disorder with or without agoraphobia's emerging. Although the cause of this comorbidity remains controversial, the main explanations are that (1) cigarette smoking promotes panic by inducing respiratory abnormalities/lung disease or by increasing potentially fear-producing bodily sensations, (2) nicotine produces physiologic effects characteristic of panic by releasing norepinephrine, (3) panic disorder promotes cigarette smoking as self-medication, and (4) a shared vulnerability promotes both conditions. The aim of this review was to survey the literature in order to determine the validity of these explanatory models. DATA SOURCES: Studies were identified by searching English language articles published from 1960 to November 27, 2008, in MEDLINE using the key words: nicotine AND panic, tobacco AND panic, and smoking AND panic. STUDY SELECTION: Twenty-four studies were reviewed and selected according to the following criteria: panic disorder with or without agoraphobia and nicotine dependence, when used, diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, Fourth Edition, or Fourth Edition, Text Revision; no additional comorbidity or, if present, adjustment for it in the statistical analyses; use of adult or adolescent samples; comparison with a nonclinical control group or application of a crossover design. DATA EXTRACTION: Non-significant results or trends only were reported as no difference. Data on anxiety disorders or substance abuse in general were not included. DATA SYNTHESIS: Panic and cigarette smoking each appear to have the capacity to serve as a causal factor/facilitator in the development of the other. Although the temporal pattern and the pathogenetic explanations of such a co-occurrence are still being discussed, cigarette smoking tends to precede the onset of panic and to promote panic itself. CONCLUSIONS: Additional studies are strongly recommended.