Gender Differences in Panic Disorder: Findings From the National Comorbidity Survey

Table 2 presents the results of the frequency analyses of panic symptoms for male and female respondents who met criteria for panic disorder or panic attacks. For both diagnostic categories and for both sexes, heart pounding was the most frequently experienced panic symptom. Between 94% and 97% of all respondents with panic disorder or panic attacks reported increased heart pounding during a panic attack. In the panic disorder group, female respondents experienced some symptoms more frequently than male respondents. For instance, a significantly greater proportion of female than male respondents complained of shortness of breath (72% versus 50%; χ²=10.8, df=1, p=0.001), feeling faint (59% versus 45%; χ²=3.7, df=1, p=0.05), and feeling smothered (60% versus 43%; χ²=5.9, df=1, p=0.02). Similarly, in the panic attack group, female respondents were more likely than male respondents to complain of shortness of breath (65% versus 50%; χ²=6.9, df=1, p=0.009), choking or difficulty swallowing (37% versus 25%; χ²=3.8, df=1, p=0.05), and feeling smothered (50% versus 38%; χ²=4.5, df=1, p=0.03). In the panic attack group female respondents were more likely than male respondents to report nausea, but the difference was not significant (40% versus 29%; χ²=3.6, df=1, p=0.06). Male respondents in both diagnostic groups endorsed pain in the stomach more often than female respondents, but the differences did not reach the level of significance (panic disorder group: 60% versus 48%; χ²=2.9, df=1, p=0.09) (panic attack group: 41% versus 40%; χ²<0.1, df=1, p=1.00).

Table 3 and Table 4 present the results of the logistic regression models specified for the panic disorder group and the panic attack group (i.e., those with history of panic of panic attacks who did not fulfill the criteria for panic disorder), respectively. These analyses confirmed that similar indicators were significant for predicting gender, including shortness of breath and nausea. Finally, scores from both groups were pooled. Five somatic symptoms entered the logistic model (Table 5). Three symptoms predicted female gender: shortness of breath (odds ratio=1.9, 95% CI=1.3–2.8), nausea (odds ratio=1.8, 95% CI=1.2–2.8), and feeling smothered (odds ratio=1.5, 95% CI=1.0–2.2). Two symptoms predicted male gender: sweating (odds ratio=0.6, 95% CI=0.4–0.9) and pain in the stomach (odds ratio=0.6, 95% CI=0.4–0.9).

Overall, the results of this study indicate that gender differences in specific symptoms exist both for subjects who meet the criteria for panic attacks and for those who meet the criteria for panic disorder. Specifically, a significantly greater proportion of female subjects experienced respiration-related symptoms (difficulty breathing, feeling faint, and feeling smothered) during panic attacks. Certain pathophysiological mechanisms may be relevant in elucidating these gender differences in respiratory symptoms during panic attacks.

To demonstrate how respiration potentially mediates bodily symptoms in panic, several experimental studies have used CO₂ inhalation and lactate infusion to induce hypocapnic states in panic-prone individuals. These two challenge techniques are perhaps the most reliable experimental panic-onset stimulants; furthermore, the potential physiological significance of the two techniques, which produce a shortage of oxygen, may be similar. Of particular relevance to our findings is the study by Papp et al. (6), who found that the physiological response to CO₂ in female panic disorder patients differed significantly across multiple indicators, including at-rest breathing rate and end-tidal CO₂. In addition, in the same study, female panic disorder patients, compared to male patients, showed greater CO₂ sensitivity, as illustrated by their higher respiratory rate. These findings suggest that female panic disorder patients may have a low threshold for panic attacks during hypoxic and hypercapnic states and are consistent with suggestions that a hypersensitive suffocation false alarm may be particularly implicated in panic disorder in female patients (7).

Our findings are limited by the retrospective nature of assessments in this epidemiological study. Additional studies are necessary to test the finding that female subjects experience more breathing problems during panic attacks, compared with male subjects. In addition, a potentially interesting group is female patients with premenstrual dysphoric disorder. To our knowledge, these patients constitute the only diagnostic group to show parallel panic and respiration responses to challenges with CO₂ and lactate (8, 9). Prospective studies with panic disorder and premenstrual dysphoric disorder patients may shed further light on gender-based differences in panic symptoms.

Received Nov. 9, 2000; revision received May 1, 2001; accepted June 1, 2001. From Stanford University and the VA Palo Alto Health Care System; and Columbia University and New York State Psychiatric Institute, New York. Address reprint requests to Dr. Sheikh, VA Palo Alto Health Care System (116A-MP), 795 Willow Rd., Menlo Park, CA 94025; [email protected] (e-mail). The National Comorbidity Survey was supported by NIMH grants MH-46376 and MH-49098, a supplement to grant MH-46376 from the National Institute on Drug Abuse, and grant 90135190 from the W.T. Grant Foundation.