Schizophrenia - Interviewing strategies

The current most widely accepted approach for diagnostic interviewing in psychiatric assessment is the use of structured interviews. The main advantage of structured interviews is that they provide a standardized approach for gathering information, which increases the (interrater) reliability of the assessment. Another advantage is that they provide guidelines for determining whether a specific symptom exists or not. On the downside, to benefit fully from the advantages of structured interviews, a fair amount of training, as well as ongoing fidelity evaluation, is required. A comprehensive assessment interview should commence with evaluation of basic characteristics of the disorder, followed by frequently associated features and common comorbid diagnoses. In the following section we focus on interviewing strategies for assessing characteristic symptoms of schizophrenia, recognizing that various assessment instruments can support a given interviewing strategy.

A wide range of assessment instruments, divided primarily into self-report and interview-based instruments, have been developed to evaluate the existence and severity of psychiatric symptoms. The Structured Clinical Interview for DSM-IV (SCID; First, Spitzer, Gibbon, & Williams, 1995) is the most widely used diagnostic assessment instrument in the United States for research studies with persons who have psychiatric disabilities. Psychiatric rating scales based on semistructured interviews have also been developed to provide a useful, reliable measure of the wide range of psychiatric symptoms commonly present in people with psychiatric disorders. These scales typically contain from 1–50 or so specifically defined items, each rated on a 5- to 7-point severity scale.

Some interview-based scales have been developed to measure the full range of psychiatric symptoms, such as the Brief Psychiatric Rating Scale (BPRS; Overall & Gorham, 1962) and the Positive and Negative Syndrome Scale (PANSS; Kay, Opler, & Fiszbein, 1987), whereas other interview-based scales have been designed to tap specific dimensions, such as the Scale for the Assessment of Negative Symptoms (SANS; Andreasen, 1982). The same classification holds true for self-report scales.

Interview-based psychiatric rating scales typically assess a combination of symptoms elicited through direct questioning and symptoms or signs observed in the course of the interview, as well as symptoms elicited by collateral history taking (from caregivers and clinical documentation). For example, in the BPRS, depression is rated by asking questions such as "What has your mood been lately?" and "Have you been feeling down?".

Ratings of mannerisms and posturing, on the other hand, are based on the behavioral observations of the interviewer. Psychiatric symptom scores can either be added up for an overall index of symptom severity, or summarized in subscale scores corresponding to symptom dimensions, such as negative, positive, and comorbid (affective and other) symptoms.