Patient attrition in a comparative outcome study of depression. A follow-up report

Eighty-seven moderately to severely depressed psychiatric outpatients were randomly assigned to 12 weeks of cognitive therapy (n = 24), pharmacotherapy (n = 24), cognitive therapy plus pharmacotherapy (n = 22) or cognitive therapy plus active placebo (n = 17). Seventy patients completed the treatment protocol; 17 dropped out before the end of the treatment period. Completers and dropouts did not differ at pretreatment on demographic variables, measures of depression, cognitive functioning or social adjustment. Sixteen of the 17 patients who dropped out were followed up and interviewed to assess their clinical status and reasons for discontinuing treatment. Neither group remained depressed at follow-up. Practical matters and issues related to the type of treatment received seemed to contribute most to patients' decision to drop out. Patients assigned to the combination therapies were more likely to complete the research protocol than those assigned to single treatment modalities. These findings are discussed in terms of their implications for clinical practice and outcome research.