"Depression is common, with the 1-year prevalence rate of major depressive disorder estimated at between 6.6 percent and 10.3 percent in the general population and roughly 25 percent of all primary care visits involving patients with clinically significant levels of depression. Psychotherapy is effective at treating depression, and most primary care patients prefer psychotherapy to antidepressant medication. When referred for psychotherapy, however, only a small percentage of patients follow through. Attrition from psychotherapy in randomized controlled trials is often 30 percent or greater and can exceed 50 percent in clinical practice," according to background information in the article. The discrepancy between patients' preference for psychotherapy and the low rates of initiation and adherence is likely due to access barriers, such as time constraints, lack of available and accessible services, transportation problems, and cost. "The telephone has been investigated as a treatment delivery medium to overcome access barriers, but little is known about its efficacy compared with face-to-face treatment delivery."

David C. Mohr, Ph.D., of the Northwestern University Feinberg School of Medicine, Chicago, and colleagues compared face-to-face cognitive behavioral therapy vs. a telephone-administered cognitive behavioral therapy for the treatment of depression in primary care. The trial included 325 patients with major depressive disorder, recruited from November 2007 to December 2010. Participants were randomized to 18 sessions of T-CBT or face-to-face CBT. The primary measured outcome for the study was attrition (completion vs. non-completion) at post-treatment (week 18). Secondary outcomes included measures of depression.

The researchers found that significantly fewer participants discontinued T-CBT (n = 34; 20.9 percent) before session 18 compared with face-to-face CBT (n = 53; 32.7 percent). Attrition before week 5 was significantly lower in T-CBT (n = 7; 4.3 percent) than in face-to-face CBT (n = 21; 13.0 percent), but there was no significant difference in attrition between sessions 5 and 18. T-CBT patients attended significantly more sessions than those receiving face-to-face CBT.

"The effect of telephone administration on adherence appears to occur during the initial engagement period. These effects may be due to the capacity of telephone delivery to overcome barriers and patient ambivalence toward treatment. Access barriers likely exert their effects early in treatment, and thus the effect of the telephone on overcoming those barriers is most prominent in the first sessions," the authors write.

In terms of changes in level of depression, the researchers found that T-CBT was not inferior to face to face CBT in reducing depressive symptoms at posttreatment. However, face-to-face CBT was significantly superior to T-CBT during the 6-month follow-up period. By 6-month follow-up, 19 percent of T-CBT vs. 32 percent of face-to-face CBT participants were fully remitted.

"The findings of this study suggest that telephone-delivered care has both advantages and disadvantages. The acceptability of delivering care over the telephone is growing, increasing the potential for individuals to continue with treatment," the authors write. "The telephone offers the opportunity to extend care to populations that are difficult to reach, such as rural populations, patients with chronic illnesses and disabilities, and individuals who otherwise have barriers to treatment. … "However, the increased risk of posttreatment deterioration in telephone-delivered treatment relative to face-to-face treatment underscores the importance of continued monitoring of depressive symptoms even after successful treatment."