How do clinicians arrive at diagnostic decisions? In most cases the decision is not made following formal criteria, but by intuition. In addition, routine interviews are often narrow and the feedback gleaned from patients is inadequate. Yet it is not clear if screening helps or hinders clinical judgment. It might be that only clinicians who have low confidence and interviewing and diagnostic skills are open to the use of and actually helped by diagnostic tools. To provide a theoretical framework for understanding why it is difficult for physicians to detect depression in primary care settings, a broad array of research in the mental health fields can be described. For example, more than 1,000 studies have been conducted on clinical judgment in the area of mental health practice, and the results from these studies can be used to illuminate the challenges physicians face in judging whether a patient is clinically depressed and can benefit from treatment. In this chapter, results on clinical judgment will be described. A second topic will also be briefly discussed. Results from research on clinical judgment would seem to indicate that screening should be of value. Yet, as noted in Chapter 7, stand-alone screening programs have added little or nothing to outcomes. Reasons for this unexpected result will be explored. Three topics will be discussed: (1) narrowness of interviews, (2) nature of patient feedback, and (3) the cognitive processes of clinicians. Depression goes undetected because in many cases physicians do not ask patients if they have symptoms of a depressive mood disorder.3 To place this in context, it can be noted that mental health professionals also often do not ask patients about important symptoms and behaviors. Failure to inquire about depression in primary care settings can be viewed in the broader context of failure to inquire about important symptoms and events in mental health settings. Research on clinical judgment has demonstrated that lack of comprehensiveness is often a problem for interviews made in clinical practice. For example, in one study,4 mental health professionals saw patients in routine clinical practice, and afterwards research investigators conducted semi-structured interviews with the patients. Remarkably, the mental health professionals had evaluated only about 50% of the symptoms that were recorded using the semi-structured interviews.
