IMPACT: Improving Mood -- Promoting Access to Collaborative Treatment

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In the largest treatment trial for depression to date, a team of researchers led by Dr. Jürgen Unützer followed 1,801 depressed, older adults from 18 diverse primary care clinics across the United States for two years. The 18 participating clinics were associated with eight health care organizations in Washington, California, Texas, Indiana and North Carolina. The clinics included several Health Maintenance Organizations (HMOs), traditional fee-for-service clinics, an Independent Provider Association (IPA), an inner-city public health clinic, and two Veteran's Administration clinics.

Half of the patients were randomly assigned to receive the care normally available in their primary care clinic, including medications (70% of usual care patients) and/or referral to specialty mental health. The other half of patients were randomly assigned to receive the IMPACT model of depression care, also known as Collaborative Care. A patient registry (CMTS) was developed for the trial that tracked and measured patient goals and clinical outcomes, and facilitated treatment adjustment if a patient was not improving as expected.

As reported in JAMA in 2002, Collaborative Care more than doubled the effectiveness of depression treatment for older adults in primary care settings. At 12 months, about half of the patients receiving Collaborative Care reported at least a 50 percent reduction in depressive symptoms, compared with only 19 percent of those in usual care. A handout of usual care versus IMPACT care presents some reasons why the results were as significant as they were. Analysis of data from the survey conducted one year after IMPACT resources were no longer available showed that the benefits of the IMPACT intervention persisted after one year. IMPACT patients experienced more than 100 additional depression-free days over a two-year period than those treated in usual care. An IMPACT study slide set describes the results, methods, and Collaborative Care model used in the original IMPACT Study.

Since the end of the trial, hundreds of organizations in the United States and internationally have adapted and implemented Collaborative Care with diverse patient populations and for a variety of behavioral health conditions.


The AIMS Center no longer offers the free 13-module program in IMPACT care (Collaborative Care). Please contact the AIMS Center at with any questions or comments. 

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