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May 24, 2007 (San Diego) — Panic disorder, which past studies have associated with smoking, is similar in severity between smokers and nonsmokers, a new study suggests. However, in this cohort, depression scores were higher for smokers than nonsmokers.

The findings were presented here at the American Psychiatric Association 2007 Annual Meeting.

"In this study, all the patients had panic disorder," first author Rafael Freire, MD, a psychiatrist at the Federal University of Rio de Janeiro, told Medscape. "We found no differences regarding its severity in smokers and nonsmokers, although there are studies that indicate there are more panic disorders in smokers than nonsmokers."

Smoking and Anxiety

Several studies have indicated a correlation between smoking and anxiety disorders, especially panic disorder, the authors write. The purpose of the new study was to investigate associations between smoking and the severity of panic disorder, as well as the prevalence of comorbidities.

A total of 61 patients were included in the study. They were diagnosed by a psychiatrist with panic disorder, agoraphobia, and depression using the Structured Clinical Interview/SCID-I for Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) Axis I disorders. Patients who had stopped smoking within the past 12 months were included as smokers. There were 39 nonsmokers and 22 smokers.

Every patient was given a Clinical Global Impression (CGI) score as a measure of symptom severity. Included in their assessment were age, sex, family income, family history of panic disorder, age of panic-disorder onset, and the presence of comorbidities such as agoraphobia and depression. Results were analyzed by t test and
Χ2 test.

The mean age of the nonsmokers was 39 years, that of smokers, 42.4 years; the 2 groups were fairly evenly divided between males and females and similar as to family income, family history of panic disorder (present in 38.5% of nonsmokers and 40.9% of smokers), and age of panic-disorder onset (mean of 31.5 years in nonsmokers, 31.0 years in smokers).

They report that CGI scores reflecting the gravity of panic disorder were similar between smokers and nonsmokers. Similarly, for comorbidities, the prevalence of agoraphobia was not significantly different, but the prevalence of major depression was significantly higher in the smokers vs nonsmokers (P = .006).

Gravity of Panic Disorder, Agoraphobia, and Depression in Smokers vs Nonsmokers

Disorder

Smokers

Nonsmokers

Gravity of panic disorder — Clinical Global Impression score

4.1

3.8

Agoraphobia (%)

86.4

71.8

Depression (%)

77.3

41


Less Successful Smoking Cessation?

Nora Volkow MD, director of the National Institute on Drug Abuse, commented, "Similar to other comorbidity pairings, causal relationships between panic disorder and smoking (in either direction) cannot be established at this time. Albeit small, the literature pertaining to panic-relevant factors and smoking behavior has indicated that panic-related factors may relate to difficulties in quitting smoking. Those less successful in quitting smoking may be more likely to suffer from psychiatric vulnerabilities."