Persistent psychiatric illnesses are a major national health care challenge (1
). These persistent illnesses include depressive and anxiety disorders. Although these common psychiatric disorders are often time limited, substantial morbidity and social burden arises from the population of individuals who remain persistently ill (2
). A study from the Netherlands found that 20% of adults with new onset of major depression remained ill at 24 months (4
). Research in treatment settings has found that anxiety and depressive disorders are often persistent, with substantial morbidity (5
Both antidepressant medication and cognitive-behavioral psychotherapy are effective in treating persistent depression (3
). Research also supports the efficacy of cognitive-behavioral therapy, certain antidepressant medications, and benzodiazepines for persistent panic and generalized anxiety disorder (8
). However, relatively little is known about the national prevalence of persistent anxiety and depressive disorders in the United States or about treatment use in this population. It would be valuable to know which individual characteristics affect treatment use and how often providers and health care organizations respond to persistent psychiatric illness by increasing the likelihood and intensity of treatment.
Researchers have been able to accurately estimate the overall national prevalence of depressive and anxiety disorders (12
). In this population, treatment rates are increasing (12
), though treatment is still received by only about one-third of affected individuals (16
). However, it has not been possible to characterize treatment use and the quality of treatment in the population of individuals with persistent
depressive and anxiety disorders. Very few studies have surveyed nationally representative samples at more than one time point (4
). The Epidemiologic Catchment Area study conducted a 15- year follow-up in Baltimore and found a median duration of eight to 12 weeks for major depression (18
). The National Comorbidity Study assessed outcomes at ten years and found that outcomes were worse among those who had greater illness severity at baseline (19
). Most research on persistent depression and anxiety has been conducted in specialty treatment settings (20
) or selected primary care practices (21
). Because the majority of affected individuals receive no treatment, studies from treatment settings cannot be used to characterize the overall population with persistent anxiety and depression.
Most individuals with acute depression are encountered in primary care. When treatment is initiated in primary care, many patients have good clinical, quality-of-life, and employment outcomes (22
). For those with treatment-resistant disorders, however, there may be a particular need for consultation with and treatment from mental health specialists. In persistent depression, research supports the use of antidepressant medication combined with psychotherapy (3
) and of multiple sequential antidepressant medication trials (23
). Access to both of these is often limited in primary care. In response, researchers have implemented and demonstrated the effectiveness of “stepped” care models that facilitate the involvement of psychiatrists, increase treatment intensity, and improve outcomes (24
It is not known nationally whether treatment rates are increasing for people with persistent illness or whether treatment intensity increases over time. A better understanding of problems in the quality of treatment could inform the development of interventions and policy to improve care. This study tracked 1,642 adults with probable major depression, dysthymia, panic disorder, or generalized anxiety disorder. Participants were drawn from a nationally representative sample and interviewed at baseline and approximately 32 months later. Because this was an observational study, the data cannot be used to estimate the effectiveness of treatments. Rather, the study evaluated whether treatments of known efficacy were delivered to individuals who were likely to benefit. The aim of this study was to provide national estimates of the prevalence of persistent depression and anxiety, and within this population, estimates of illness severity, treatment use, and treatment quality.