Panic disorder (PD) is a severe anxiety disorder that affects more than 6 million Americans. It is characterized by the presence of recurrent unexpected panic attacks and a persistent worry about future panic attacks and their consequences. The lifetime prevalence of PD ranges from 1 – 3% in the general population, and 3.0 – 8.3% of patients in clinical settings meet criteria for current PD. [2-4] Psychiatric comorbidity and work impairment are common among PD patients, and although they are rarely diagnosed with severe medical conditions, their health-care service utilization is high.
PSYCHIATRIC COMORBIDITIES IN PD
PD frequently coexists with other psychiatric disorders with as many as 80% of individuals with PD having a comorbid psychiatric diagnosis. Major depressive disorder (MDD) is the most common comorbid psychiatric condition affecting between 32 and 70% of individuals with PD,[1,2,6] and recent reports suggest that half of those diagnosed with MDD will experience a panic attach in their lifetime. Studies show that other anxiety disorders, bipolar disorder, and psychosis also frequently co-occur with PD.[7-9] Nearly 42% of patients with PD had comorbid generalized anxiety disorder, and bipolar disorder was eight times more common among patients with panic attacks compared to those without such attacks. Patients with PD also are more likely to have alcohol or substance abuse problems.[9,10]
Suicide attempts are more prevalent in comorbid PD and depression than in either condition alone. The National Comorbidity Survey (NCS) noted that the prevalence of suicide attempts was 5.2% for PD cases, 16% for depressed individuals, and 25% for persons with both conditions. Another study noted an increased risk of suicide attempts among PD sufferers (7% of PD patients compared to 1% of those without a psychiatric disorder).
EMPLOYMENT STATUS, WORK PRODUCTIVITY, AND DISABILITY
A wide range of evidence suggests that PD is associated with a decrease in quality of life and impairment in several domains of functioning including work. Rates of unemployment in PD populations are approximately 25%, and one study noted that only 57% of PD sufferers were employed on a full-time basis.[12,13] In another sample, 14 of 30 patients were unemployed, 11 had at some time either quit or lost their jobs due to emotional distress, and 13 reported that they were completely unable to work for 1 month or more. PD is also associated with missed work days among those who do work. It is estimated that people with untreated PD miss an average of 12 working days per year compared to 5.2 days missed by the general US population. Studies report that 44% of respondents with PD missed one or more workdays due to emotional reasons over a 3-month period compared to only 2% of subjects without any mental health disorders and that those with PD were 27 times more likely than those in the general population to have a work loss day due to emotional circumstances. Other studies indicate that individuals with PD averaged 1–2 work loss days and 3–5 work cutback days per month,[17,18] and that 52% of those with PD reported work impairment, with an average of five impairment days in the previous month.
Due to impairments in employment functioning, individuals with PD experience relatively high rates of welfare and disability compensation. One study found that persons with PD were 3.3 times more likely to receive disability payments than those without the disorder. In another study that measured financial dependency, 27% of people with PD received welfare.
DIRECT COSTS OF PD
PD patients utilize health-care services at higher rates than any other psychiatric disorder, and PD visits are associated with high costs. PD is associated with increased laboratory medical care costs, high utilization of medical ambulatory services, and excessive visits to the emergency room. PD often is treated in an emergent setting; 57% of PD patients initially seek treatment at a hospital emergency department, and of those patients, 49% continue to use the ER for additional treatment. Approximately 35% of patients with PD visit their general family practitioner and continue to receive treatment with their primary physician instead of seeking treatment from a mental health specialist. Approximately 19% of PD patients, with inadequate information on their disorder, are initially seen at a nonprofessional site, and 13% of these patients continue treatment at these sites. PD frequently is unrecognized and the symptoms mimic a variety of dangerous medical conditions; therefore, patients often are given a variety of expensive tests to rule out physical abnormalities (e.g., echocardiogram, $350; Holter monitoring, $200; treadmill testing, $150). PD patients also frequently present with chest pain, which leads to emergency treatment including angiography.
The direct costs of PD treatment increase significantly over time. Although the annual cost of treatment 1 year before diagnosis is $29,158, the cost of treatment 1 year after diagnosis is $46,256. PD patients can offset the increase in direct costs with a significant decrease in indirect costs, thanks to proper screening and care for their anxiety.[26,27] The indirect costs of PD treatment decreases from $65,643 to $13,883 annually because proper treatment results in other benefits such as increased attendance at work.
Although psychiatric comorbidities among panic sufferers are relatively well documented, subthreshold panic has only started to undergo the same scrutiny. Several studies have described the prevalence and impact of subthreshold panic,[16,20,25,29,30-37] and a few have investigated the presence of comorbidities in people with subthreshold panic.[38-40] Additionally, some studies have noted that panic may be a precursor of more severe psychopathology.[8,28,41-43] The purpose of this study is to add to the accumulating evidence of significant comorbidity and disability associated with subthreshold PD. Work productivity and health-care utilization (e.g., primary care visits, specialty care visits, emergency visits, cost of care) among subjects with PD as well as subjects with varying degrees of subthreshold panic was also examined. This study is unique in that it utilizes a very large population-based sample of over 900 individuals, oversampled for people with lower SES and those who use primary care for the treatment of their mental disorder. This study, in addition to other samples, calls to provide better recognition and care for people in these populations.