Development and Validation of a Measure of Patients' Knowledge About Schizophrenia

The Knowledge About Schizophrenia Questionnaire (KASQ) was derived from a pool of 78 items, including 13 items from a measure devised originally for relatives of patients with schizophrenia (4). Items were aimed at measuring patients' knowledge about the diagnosis of schizophrenia and its prevalence, etiology, course, and prognosis, as well as medication and side effects, nondrug treatments, stress factors, and legal issues. A total of 25 items were judged by four educators to best reflect the content areas covered in a psychoeducation program for patients diagnosed as having schizophrenia (10). A copy of the KASQ is available from the author.

Participants were 136 adult inpatients at a Midwestern state psychiatric facility, diagnosed using DSM-IV criteria as having schizophrenia (128 patients, or 94 percent) or a schizoaffective disorder (eight patients, or 6 percent). Eighty-two patients (60 percent) were male, and 121 (89 percent) were single. A total of 124 patients (91 percent) had a high school education or less. The mean±SD age of the patients was 35±11.4 years (range, 18 to 58 years). All participants were undergoing a medication regimen with antipsychotic medications.

The patients participated in four studies conducted between February 1990 and April 1995. Patients were referred by their treatment teams to the group education program, which offers daily one-hour sessions over a three-week period and which is led by various mental health professionals. Study 1 involved administration of the KASQ before and after participation in the 15-session educational intervention. Study 2 proceeded with cross-validation, by repeating study 1 with a different sample of 53 patients who participated in the education program about a year later. Study 3 involved test and retest, at a three-week interval, of ten patients who did not participate in previous studies and did not attend the education program.

Studies 1 and 2 included 53 patients each, and study 3 involved ten patients. Study 4, a controlled study, involved 20 patients, all diagnosed as having schizophrenia, whose mean± SD age was 36±10.8 years. In study 4 the mean±SD number of previous hospitalizations for the 20 patients was 5.7±2.9, and the mean±SD number of years of education was 12.5± 2.9. All 20 patients were single, and 13 patients (65 percent) were male. The mean±SD current Global Assessment of Functioning score for the patients in study 4 was 33±8.3.

Study 4 involved random assignment of 20 patients to the education group or a waiting-list control group. Each group completed the test twice—the former group completed it before and after the intervention, and the latter group waited three weeks before taking it a second time. The groups did not differ significantly in gender, age, or marital status. Individual differences in guessing tendency were kept under control by instructing patients to guess on every item that they were unable to answer. Attempts were made to balance the response formats by varying the frequency of the correct alternative and the number of alternatives per item.

This study found that the Knowledge About Schizophrenia Questionnaire has sound psychometric properties. Its reliability, as measured by precision, internal consistency, and stability indicators, is high, and its sensitivity to change indicates good construct validity. These properties, which were replicated in a cross-validation study, along with its ease of administration and scoring, support its use in outcome studies in which comprehensive patient education about schizophrenia is provided.

However, because this measure was initially constructed to evaluate a particular education program (10), it may not be readily applicable to other education programs. Thus the utility of the KASQ may be restricted to this and similar education programs that go beyond education about medication management and include information about the diagnosis of schizophrenia, its prevalence, etiology, course, prognosis, nondrug treatments, stress factors, and legal issues. This type of comprehensive patient education is becoming more prevalent partly due to growing emphasis on psychosocial rehabilitation and patient empowerment and partly due to the need to meet standards of care for patient education mandated by the Joint Commission on Accreditation of Healthcare Organizations.

The KASQ's psychometric properties appear comparable to those of the ERWIPA, a German instrument for evaluating patients' knowledge of their illness (8). However, no underlying factor structure for the KASQ was demonstrated, nor does it have alternate forms. (A parallel or alternate form of an instrument tends to have similar psychometric properties, which allows repeated measures without concern for the effect of memory on retesting.) The KASQ was found to be more reliable than the ERWIPA, and patients' KASQ scores were shown to be stable over time. In addition, the KASQ has varied response alternatives (in addition to true, false, and do not understand), and a cross-validation study of the KASQ confirmed its reliability.

The author thanks Ann Claveaux, M.A., Sandra Rochford, R.N., Donna Cisco, C.C.S.W., and Eric Martin, Ph.D., for assistance with the patient education program and the outcome projects.

Dr. Ascher-Svanum is chief psychologist in the general psychiatry service of Larue Carter Hospital, 2601 Cold Spring Road, Indianapolis, Indiana 46222-2202 e-mail, [email protected]. She is also assistant professor of clinical psychology in the psychiatry department at Indiana University School of Medicine. An earlier version of this paper was presented at the annual meeting of the American Psychological Society held June 29-July 2, 1996, in San Francisco.