Structured interviews, standardized data forms, questionnaires, and rating scales can be useful tools for diagnostic assessment and evaluation of treatment outcome. Table 3, while not all-inclusive, lists many of the common structured instruments in use (see also the CD-ROM from APA's Handbook of Psychiatric Measures [118]). Such structured instruments may be used as components for establishing a diagnosis, measuring social or occupational function, or monitoring changes in symptom severity or side effects over time during treatment.

Although most commonly used in psychiatric research, rating scales may also help psychiatrists structure a thorough line of questioning. In addition, self-report scales may be valuable in opening communication with patients about their symptoms, feelings, or experiences. At the same time, these tools vary considerably as to their reliability and validity. Potential cultural, ethnic, gender, social, and age biases are relevant to the selection of standardized interviews and rating scales and the interpretation of their results (119–125). Furthermore, clinical impressions of treatment response should consider the relative importance of specific symptoms to the patient's function and well-being and the relative impact of specific symptoms on the patient's social environment. Consequently, rating scales should never be used alone to establish a diagnosis or clinical treatment plan; they can augment but not supplant the clinician's evaluation, narrative, and clinical judgment (11, 126–129).

For persons with chronic diseases, and particularly those with multiple comorbid conditions, structured assessment of physical and instrumental function may be useful in assessing strengths and disease severity (130). Functional assessments include assessment of physical activities of daily living (e.g., eating, using the toilet, transferring, bathing, and dressing) and instrumental activities of daily living (e.g., driving or using public transportation, taking medication as prescribed, shopping, managing one's own money, keeping house, communicating by mail or telephone, and caring for a child or other dependent) (131, 132). Impairments in these activities can be due to physical or cognitive impairment or to the disruption of purposeful activity by the symptoms of mental illness.

Formal assessment of physical and instrumental activities of daily living may be appropriate for patients who are disabled by old age or by chronic mental illness or general medical conditions. Such assessments facilitate the delineation of the combined effects of multiple illnesses and chronic conditions on patient's lives, and such assessments provide a severity measure that is congruent with patients' and families' experience of disability. In addition, functional assessment facilitates the monitoring of treatment by assessing important beneficial and adverse effects of treatment.