Over the last three decades, tremendous progress has been made by mental health services researchers in improving recognition and quality of treatment for patients with affective disorders within primary care systems. In the United States, this research was initially stimulated by the findings from the Epidemiology Catchment Area Study that showed that over half of the community respondents in the United States with depressive and anxiety disorders were treated exclusively in primary care settings [1
]. This finding led Regier et al. [1
] to label the primary care system the “de facto” mental health care system of the United States.
During the 1980s and early 1990s, health services researchers documented that 5% to 12% of primary care patients met DSM-IV
criteria for major depression [2
]. Patients with major depression in primary care systems were also shown to have high numbers of medically unexplained symptoms [3
], a greater degree of comorbid medical illness [4
], as much or more functional impairment as patients with other common medical disorders such as diabetes or heart disease [5
], and up to twofold higher medical utilization and costs [6
Researchers in the 1980s and 1990s also documented the gaps in quality of depression care in primary care systems. Studies showed that only 25% to 50% of patients with depression were accurately diagnosed by primary care physicians and, among those who were accurately diagnosed, few received adequate dosage and duration of either pharmacotherapy or evidence-based depression psychotherapy [8
]. Naturalistic primary care-based studies found that approximately 40% of patients discontinued antidepressants in the first 4–6 weeks of treatment [10
]. This was largely because the frequency of follow-up in primary care clinics was quite limited: the median performance of 247 health plans on the HEDIS depression performance criteria that recommended that patients initiating treatment with an antidepressant have three follow-up visits in the first 90 days has been only 20% for over a decade [11
]. Even when close follow-up occurs, treatment is often not adjusted according to need, based on severity of residual symptoms [12
]. Large-scale studies have also shown that approximately 40% to 50% of patients with depression referred by primary care doctors to mental health specialists fail to complete the referral [13
]. The result is that only approximately 40% of primary care patients with depression who were accurately diagnosed recovered over a 4- to 6-month period [14
]. These gaps in treatment were documented to be even more problematic in minority populations and in those living below US poverty levels [15
Early research attempts to improve quality of care and outcomes of patients with depression and anxiety in primary care tested whether providing physicians with evidence of depression based on depression rating scales would increase detection, provision of evidence-based treatment and enhanced outcomes. These studies randomized patients screening as depressed into two groups: patients whose physicians were notified of their depression status vs. those in whom physician notification did not occur. These studies showed that physician notification of depression status resulted in slight improvements in quality of depression care, but no replicable effects on improved depression outcomes [16
]. Several later studies built on these initial failures to attempt to enhance depression outcomes by randomizing depressed primary care patients into those whose physicians were notified about a major depression diagnosis and provided with an algorithm of recommended depression care vs. those allowed to remain in usual care [17
]. Again, no replicable effects on patient-level outcomes were demonstrated.
From 1990 to 1996, NIMH with help from AHRQ funded nine depression collaborative care trials [19
]. These trials were developed during the same era in which Wagner et al. [20
] at Group Health in Seattle described four key elements of the organization of care that must be implemented to improve outcomes of populations of patients with chronic illness: the delivery system must be designed so that each patient's care includes proactive follow-up visits or telephone contacts, adherence monitoring and response to treatment assessments; information systems must be established to support the use of disease registries to track provision of care according to guideline and individual treatment plans; self-management training and support must be provided to patients and key family members so that they are equipped with the information and skills required to effectively manage their illness in order to develop an active partnership with the health care team; and decision support must be provided to primary care physicians, including facile access to guidelines, expert systems and specialty consultation within the context of a structured care program. Wagner et al. [20
] emphasized that these organizational changes in practice usually required a team approach with an allied health professional such as a nurse providing the close monitoring and frequent contacts.
The key components of collaborative depression care developed for these initial federally funded trials included many of the key components of Wagner et al. [20
], such as enhanced patient education with pamphlets, books and videotapes; use of either allied health professionals such as nurses or mental health professionals to provide closer follow-up to track outcomes, side-effects and adherence to treatment; use of a tool such as the Patient Health Questionnaire-9 (PHQ-9) to track outcomes, and development of an electronic depression register to facilitate caseload supervision; a psychiatrist to provide caseload supervision of depression care managers and recommendations about changes in antidepressant medication; and stepped-care approaches that provided incremental increases in treatment for patients with persistent symptoms [22
]. In some of these trials, depression case managers could also provide an option of brief evidence-based psychotherapy [22
]. These collaborative care approaches enhanced the systematization and organization of primary care practice to provide closer follow-up; patient education and monitoring of symptoms, side-effects and adherence; and integrated specialty knowledge about antidepressant medication into primary care practice.
A recent meta-analysis reviewed 37 trials of depression collaborative care and found evidence compared to usual primary care of twofold higher rates of adherence to antidepressant medication over the first 6 months of treatment and improved depressive outcomes that often persisted for at least 2 years [23
]. Six new trials have also tested collaborative care approaches to treating depression in patients with a chronic medical illness (diabetes, cancer, stroke and post-coronary bypass grafting surgery) and found significant improvements in quality of care and depressive outcomes compared to usual care [24
]. Cost-effectiveness analyses demonstrated that total ambulatory costs associated with collaborative care increased approximately $125 to $600, but with significant and substantial gains in depression-free days over a 1- to 2-year period [23
]. In some studies of more complex depressed patients, including those with major depression and diabetes [31
], panic disorder and major depression [33
], and those with ≥4 DSM-IV
symptoms of major depression 8 weeks after the primary care doctor-initiated antidepressant treatment [35
], there was evidence of a high probability of savings in total medical costs associated with collaborative care.
A key problem in the US health care system is that minority populations and people living below US poverty levels have been shown to have marked disparities in access to quality mental health care [15
]. Several of the larger multisite collaborative care studies examined whether the benefits of this care model were found in populations living below US poverty levels and in minority patients. A recurrent finding from these trials has been that patients living below poverty levels and patients from ethnic minority groups have experienced equal or even greater benefits from collaborative care vs. usual care as Caucasian or more middle-class populations [25
]. shows data from the eight sites involved in the IMPACT trial that randomized 1801 adults age 60 and older from eight health care organizations in five states of the USA. Study sites with high proportions of ethnic minority participants (African Americans and Latinos) had similar or greater incremental collaborative vs. usual care differences in depression outcomes as sites serving largely whites [29
]. More recent studies in which the collaborative care programs for depression were tested in primarily low-income ethnic minority groups confirm the relative effectiveness of this approach [25
IMPACT: Depression outcomes are robust across eight diverse clinics and populations.