Depression is common, disabling, and often unrecognized in general medical practice. Even when recognized, physicians frequently do not provide systematic, longitudinal evidence-based management. And from the perspective of the patient, stigma and other psychosocial barriers often diminish adherence to treatment recommendations. Therefore, despite robust documentation that depression is quite treatable and the widespread availability of evidence-based guidelines, overall outcomes remain poor.
This chapter focuses on the core knowledge and skills needed by general medical practitioners to effectively assess and manage major depressive disorder (MDD). We briefly address several other related mood disorders: dysthymic disorder, adjustment disorder with depressed mood, depression secondary to general medical conditions, bipolar disorder/bipolar depression, and melancholia. Of core importance, we emphasize the routine use of a brief patient self-assessment tool, the nine-item Patient Health Questionnaire (PHQ-9), for diagnostic and ongoing management purposes. Widespread adoption of this one practice innovation may provide the pivotal leverage needed to improve outcomes for depression.
Major depressive disorder is associated with considerable disability, morbidity, and mortality. Epidemiologic studies demonstrate that depression causes as much, and often more, physical disability and social and role impairment than most other chronic illnesses, such as diabetes, arthritis, hypertension, and coronary artery disease. The World Health Organization has identified major depression as the fourth leading cause of disability worldwide and projects it will become the second leading cause of worldwide disability by 2020. Major depression is also a well-documented and common comorbidity in most other chronic conditions: for example, heart disease, stroke, diabetes mellitus, cancer, Parkinson disease, arthritis, pulmonary disease, and others. Furthermore, when present as a comorbidity, depression accounts for significant increases in disability, morbidity, and mortality.
The etiologic and sustaining relationships between depression and these other conditions appear bidirectional. For example, preexisting depression has been established as a predictor of future atherosclerotic coronary artery disease, cerebrovascular disease, diabetes, and osteoporosis, and conversely, significant physical illness predicts higher prevalence of major depression compared to individuals without the physical illness. Depressed patients with heart disease (coronary artery disease, congestive heart failure) have worse medical outcomes including increased risk of reinfarction (after myocardial infarction [MI]) and up to a threefold increase in all-cause mortality (especially after MI), even after controlling for all other identifiable and measurable cardiac risks (such as overeating, sedentary lifestyle, smoking, and other predictors of poor outcome). Patients with diabetes and depression have worse glycemic control, more microvascular and macrovascular complications and greater all-cause mortality.
Major depression is associated with adverse health habits, such as smoking, poor diet, overeating, and sedentary lifestyle, all themselves contributing to the onset of general medical illness and/or poor outcomes in illness. Conversely, functional impairment stemming from these chronic illnesses predispose to development of new depression. From an etiologic perspective, variables such as genetic vulnerability, childhood adversity (neglect and abuse), and stressful life events all contribute to the development of depression itself as well as to lifestyle risks such as obesity, sedentary behavior, and ...