Compared with nondepressed patients, the odds are 3 times greater that depressed patients will be noncompliant with medical treatment recommendations. Recommendations for future research include attention to causal inferences and exploration of mechanisms to explain the effects. Evidence of strong covariation of depression and medical noncompliance suggests the importance of recognizing depression as a risk factor for poor outcomes among patients who might not be adhering to medical advice.

Overall, the outcome difference between high and low adherence is 26%. According to a stringent random effects model, adherence is most strongly related to outcomes in studies of nonmedication regimens, where measures of adherence are continuous, and where the disease is chronic (particularly hypertension, hypercholesterolemia, intestinal disease, and sleep apnea). A less stringent fixed effects model shows a trend for higher adherence-outcome correlations in studies of less serious conditions, of pediatric patients, and in those studies using self-reports of adherence, multiple measures of adherence, and less specific measures of outcomes. Intercorrelations among moderator variables in multiple regression show that the best predictor of the adherence-outcome relationship is methodological-the sensitivity/quality of the adherence assessment.

Pain is present in two thirds of depressed primary care patients begun on antidepressant therapy, and the severity of pain is a strong predictor of poor depression and health-related quality of life outcomes at 3 months. Better recognition, assessment, and treatment of comorbid pain may enhance outcomes of depression therapy.

To investigate the role of CD8+ T lymphocytes in recovery from influenza pneumonia, we used transgenic mice either homozygous (-/-) or heterozygous (+/-) for beta 2-microglobulin (beta 2-M) gene disruption. These mice lack major histocompatibility complex-restricted class I (CD8+) T cells. We found that after challenge with a nonlethal influenza virus, the beta 2-M (-/-) mice had significantly delayed pulmonary viral clearance. Furthermore, after challenge with a more virulent influenza virus, the beta 2-M (-/-) mice had a significantly higher mortality rate than did control mice. Thus, CD8+ T cells are important in recovery from virulent influenza infections, but other host defense mechanisms can clear the respiratory tract of more benign infections.