An Expert System to Reduce Depression in Primary Care

The purpose of this study is to determine whether a home-based intervention matched to stage of change (readiness) for using effective methods to prevent or reduce depression can improve depression outcomes in primary care.

A variety of effective interventions exist for people who are willing to seek help for depression. However, there is a lack of interventions for individuals who are not willing to seek help or follow through with treatment recommendations. This is the first population-based intervention for depression that is appropriate for individuals in all stages of change-not merely the minority who are prepared to take action. Two primary care samples were included: 1) patients at risk for or experiencing depression but not involved in or planning treatment (Untreated Sample), and 2) patients newly prescribed antidepressant medication (Antidepressant Sample). Patients from both samples were randomly assigned to receive the intervention consisting of telephone assessments, a stage-based workbook, and three individualized, computer-generated reports mailed to the home (n=443), or usual care (n=459). Primary outcomes, assessed at 9 months, were change in depression severity, reliable and clinically significant change in depression severity, stage of change for using effective methods or prevent or reduce depression, onset of major depression if experiencing only subclinical symptoms at baseline, and medication adherence. The study design included an examination of whether the intervention effect was moderated by primary care sample, baseline use of effective methods to prevent or reduce depression, and level of depression.

depression, stage of change, intervention, randomized clinical trial, population-based, expert system

Depression was assessed using the Beck Depression Inventory, 2nd Edition (BDI-II)(Beck, Steer, & Brown, 1996). In this self-report measure, 21 symptoms of depression are rated on a 0-3 scale. Scores for the 21 items are summed to yield a total score ranging from 0 to 63. The change scores reported here are the difference between the total BDI-II scores at baseline and 9 months (i.e., 9 months minus baseline). Change scores range from -63 to +63, with larger negative scores indicating greater reduction in depression.

Number of Participants Exhibiting a Reliable and Clinically Significant Change in Depression Severity

Two statistical criteria (Jacobson & Truax, 1991a; Atkins, Bedics, McGlinchey, & Beauchaine, 2005) were used to define reliable and clinically significant improvement. The first involved selecting a cutoff that represents remission or the absence of symptoms, which was selected to be BDI-II < 9. The second involved selecting a pre-post difference score that represents a statistically reliable change (e.g., how much change-1 point, 5 points, 10 points-is needed to be 95% confident that a real change has occurred, rather than just a chance fluctuation due to the unreliability of the measure?) Using a general formula for calculating reliable change that incorporates test-retest reliability (Jacobson & Truax, 1991b), reliable change for the BDI-II was calculated to be 5.13, and rounded down to 5. Thus, reliable and clinically significant improvement on the BDI-II was defined as a reduction of 5 or more points from baseline to follow-up and a follow-up score < 9.

Number of Participants in the Action or Maintenance Stage for Using Effective Methods to Prevent Depression.

Depression prevention was defined as: "Using effective methods to keep depression from occurring, or if it does occur, to keep it as mild and brief as possible." Effective methods were: 1) controlling negative thinking; 2) engaging in healthy, pleasant activities; 3) practicing stress management; 4) exercising; and 5) getting professional help when needed. Patients who reported that they were not currently practicing depression prevention and had no intention of doing so in the next 6 months were classified in the precontemplation stage; those who intended to practice depression prevention in the next 6 months or next 30 days were classified in the contemplation or preparation stage, respectively; those who had been practicing depression prevention for less than 6 months were in the action stage, and those who had been practicing for more than 6 months were in maintenance. This outcome represents the number of participants in the action or maintenance stage at 9 months follow-up.

Number Participants Without Major Depression at Baseline Who Experienced the Onset of Major Depression During Follow-up

At baseline and follow-up, Major Depression was assessed using 9-item depression module of the Primary Care Evaluation of Mental Disorders Patient Health Questionnaire-PHQ-9 (Spitzer, Kroenke, & Williams, 1999). In this analysis, Major Depression was assessed among participants not meeting criteria for major depression at baseline.

At 9 months follow-up, participants who had been prescribed antidepressant medication were asked if they had started and were still taking it. Participants who were taking their medication or had stopped with their doctor's advice were considered to be adherent.

Physical functioning was assessed using the Physical Functioning, Role Functioning, Health Perceptions, and Pain subscales of the 20-item Medical Outcomes Study Short Form survey (SF-20) (Stewart, Hays, & Ware, Jr., 1988). (SF-20 subscales assessing mental health and social functioning were omitted to get a purer measure of physical functioning). Physical functioning was computed by taking the mean of the four subscales after each was linearly transformed to range from 0-100. The change scores reported here are the difference between the physical functioning scores at baseline and 9 months (i.e., 9 months minus baseline). Change scores range from -100 to +100, with higher positive scores indicating more improvement in physical functioning.

Inclusion Criteria: At risk for or experiencing depression (i.e., Beck Depression Inventory-II (BDI) score of 10 or higher; current major depression, minor depression, or dysthymia; or past major depression, minor depression, or dysthymia) Exclusion Criteria: Younger than age 18 Involved in counseling or planning counseling in the next 30 days Taking antidepressant medication or planning to take antidepressants in the next 30 days (exclusion criterion for Untreated Sample only) Suicidal ideation Severe depression (BDI > 28) and deemed inappropriate for study by site clinician BDI <10 and in the Maintenance stage for using effective methods to prevent or reduce depression History of bipolar disorder

Levesque DA, Van Marter DF, Schneider RJ, Bauer MR, Goldberg DN, Prochaska JO, Prochaska JM. Randomized trial of a computer-tailored intervention for patients with depression. Am J Health Promot. 2011 Nov-Dec;26(2):77-89. doi: 10.4278/ajhp.090123-QUAN-27.