Gender Differences in Anxiety Disorders
Teresa A. Pigott and Lai T. Lac
Though rarely appreciated, anxiety disorders represent one of the most common psychiatric disorders. Nearly one out of four Americans will meet criteria for an anxiety disorder during their lifetime. Inexplicably, women are much more likely than men to develop anxiety disorders. In fact, lifetime prevalence estimates based on large-scale population surveys conducted within the US suggest that women are two to three times more likely than men to develop panic disorder (7.7% vs 2.9%), agoraphobia (9.0% vs 3.0%), simple phobia (13.9% vs 7.2%), or post-traumatic stress disorder (PTSD) (11.3% vs 6.0%). Lifetime prevalence estimates also suggest that women are 1.5 times more likely than men to develop obsessive-compulsive disorder (OCD) (3.1% vs 2.0%) or social anxiety disorder (16.4% vs 11.2%) (Robins et al., 1984; Bourdon et al., 1988; Breslau, Davis and Andreski, 1990; Regier, Narron and Rae, 1990; Kessler et al., 1994; Leon, Portera and Weissman, 1995; Magee et al., 1996; Yonkers and Ellison, 1996).
Results from the international epidemiological surveys also confirm that anxiety disorders are very common and that women have much higher prevalence rates than men. Although prevalence rates tend to decrease with advancing age, anxiety disorders remain more common in women throughout the life span (Krasucki, Howard and Mann, 1998). There is some evidence that the gender difference for anxiety disorders narrows after the age of 65. This finding, however, may represent an artifact from the combined effects of cumulative, anxiety-related mortality as well as the complex differentiation between anxiety and cognitive impairment. The narrowing of the gender difference may also result from the attenuation of hormonal factors that occurs with advancing age (Krasucki, Howard and Mann, 1998).
The presence of an anxiety disorder has important implications. A lifetime diagnosis of an anxiety disorder is associated with increased functional impairment, diminished educational and occupational opportunities, and elevated morbidity and mortality rates in comparison to the absence of an anxiety disorder. Elevated utilization rates for emergency medical and mental health care services are also linked to the presence of an anxiety disorder. Despite these adverse consequences, very few individuals with an anxiety disorder receive any type of psychiatric treatment (Lindal and Stefansson, 1993; Dick et al., 1994a, 1994b; Kessler et al., 1994, 1997; Weissman et al., 1994; Leon, Portera and Weissman, 1995).
Low recognition rates for anxiety disorders represent a significant obstacle in delaying effective treatments. Somatic symptoms, a cardinal feature of excess anxiety, may effectively obscure their primary psychiatric basis. Most anxiety disorders initially present in a general medical rather than mental health setting. Unfortunately, results from numerous studies confirm that a primary anxiety disorder is unlikely to be considered in a primary care setting until the late stages of a routine diagnostic assessment (Hohmann, 1989; Kennedy and Schwab, 1997; Roy-Byrne and Katon, 1997; Bland, Newman and Orn, 1997b; Fleet et al., 1998). Instead, anxiety is routinely relegated to the position of a diagnosis of exclusion. A number of studies have also suggested that gender differences in the presentation, attribution, and expression of anxiety symptoms may further delay the prompt recognition of anxiety disorders. Results from several studies also suggest that primary care physicians are more likely to attribute anxiety to a mood disorder, even when an anxiety disorder is primary (Rogers et al., 1994).
Anxiety and mood disorders have extensive comorbidity. Lifetime prevalence estimates, in fact, suggest that more than two thirds of anxiety disorder patients will also develop a mood disorder, particularly depression (Kessler et al., 1994). There is also substantial comorbidity between the anxiety disorders. For example, 40% of patients with OCD will also meet criteria for an additional anxiety disorder diagnosis during their lifetime (Rasmussen and Eisen, 1990; Pigott et al., 1994; Hollander et al., 1996a; Antony, Downie and Swinson, 1998). The frequent co-existence of mood and anxiety conditions may also further hinder the prompt and accurate diagnosis of anxiety disorders.
It remains unclear why anxiety disorders are so much more common in women than men. Genetic, biological, developmental, and environmental factors have all been implicated. Since anxiety and depression are both more prevalent in women than men, a shared or similar genetic basis may exist. Results from female twin studies provided some compelling support for a shared genetic diathesis between GAD and depression (Kendler et al., 1992a, 1992b). However, available evidence suggests that the remaining anxiety disorders are characterized by less genetic homogeneity (Kendler et al., 1992c, 1995).
Developmental and environmental factors are also likely to be important in the pathogenesis of anxiety disorders. Histories of childhood trauma or early separation anxiety increase the risk for both sexes that an anxiety disorder will subsequently occur (Young et al., 1997; Stein et al., 1998; Sutherland, Bybee and Sullivan, 1998). There is some intriguing evidence, however, that women may be differentially susceptible to the adverse consequences associated with childhood abuse. Breslau and colleagues have extensively investigated the impact of gender on PTSD. Their results suggest that when exposure rates are similar, women are more likely than men to develop PTSD after the occurrence of trauma. Moreover, a history of childhood trauma is a more reliable predictor in women than men that PTSD will be present as an adult (Breslau et al., 1990, 1997a, 1997b). There is also evidence that gender differences exist in the type of anxiety disorder that may develop in response to chronic environmental stress. Galbaud and colleagues investigated the potential association in psychiatric diagnoses between spouses. They found that a diagnosis of depression, drug addiction, or antisocial personality disorder in one spouse increased the chances that the spouse would meet criteria for an anxiety disorder. However, a different anxiety disorder occurred in the women versus men spouses. That is,