Coplan, 1996; Keller and Hanks, 1995; Liebowitz, 1993; Marcus et al., 1997). Of the eight anxiety disorders diagnosed via the DSM-IV, the two most frequently associated with suicide in existent studies are panic disorder (Schmidt et al., 2000) and PTSD (Kessler, 2000), discussed in turn below.
Weissman and colleagues (1989) provided the first overview of panic disorder in relation to suicide and found an almost 20-fold increased risk for suicide attempts compared to those without any psychiatric disorder. Follow-up studies of completed suicides suggest approximately 20 percent of suicide deaths are due to panic disorder (Schmidt et al., 2000). A large follow-up study in Sweden found a suicide rate for pure panic disorder comparable to major depression and other serious psychiatric illness requiring inpatient care (Allgulander and Lavori, 1991).
The comorbidity of panic disorder with other mental illnesses conveys the greatest suicide risk (Schmidt et al., 2000). In one of the few studies investigating clinical predictors of suicidality in panic disorder, Schmidt and colleagues (2000) confirmed that co-occurring agoraphobia as well as depression significantly increase risk for suicidality, but found that depression likely mediates the relationship between panic disorder and suicidality. This suggests that co-occurring depression in panic disorder may actually be a secondary disorder that develops in response to the panic disorder. This study also found that patients’ avoidance of bodily sensations and their anticipatory anxiety significantly predict suicide attempt, offering clues for assessment and intervention regarding suicidality in this population.
Post-traumatic stress disorder has demonstrated the strongest association with suicidality of any of the anxiety disorders (Kessler, 2000; Molnar et al., 2001). It predicts subsequent first onset of a suicide attempt with an odds ratio of 6, as compared to other anxiety disorders with an odds ratio of 3, and mood disorders at 12.9 times the increased risk (Kessler et al., 1999). Furthermore, PTSD appears to have an equal or greater odds ratio than mood disorders or other anxiety disorders for making a suicide plan and for making impulsive suicide attempts (Kessler et al., 1999).
Recent analyses of the data from the National Comorbidity Survey have significantly increased knowledge about PTSD within the U.S. population, including finding it far more common (7.8 percent lifetime preva-