The development, validity and reliability of psychotic symptoms rating scale for patients with schizophrenia (prasrimahabhodi assessment schizophrenia scale: PASS8)

• Main Authors: Thoranin Kongsuk, Kamonnet Wannasewok, Jetsada Thongtao, Supattra Konkhamdee, Kadsaraporn Kenbubpha, Teerapa Thanee, Jirungkoon Nuttharungsri
• Other Authors: Thailand Ministry of Public Health
• Format: Article
• Published: 2019
• Subjects: Medicine
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/47167
• Institution: Mahidol University

© 2018, Medical Association of Thailand. All rights reserved. Objective: To develop and test the validity and reliability of PASS8-a psychotic symptoms rating scale for the assessment of patients with schizophrenia which was designed for use in primary or secondary health care units. Materials and Methods: The present study consisted of 2 stages. The first stage involved the development of psychotic symptoms rating scale; it composed of 8 items, 3 dimensions, and 5-point severity rating scales. In the second stage, a crosssectional study was conducted to test the validity and reliability of PASS8 in patients with schizophrenia who were treated at Prasrimahabhodi Psychiatric Hospital. The patients were diagnosed with schizophrenia according to ICD-10 or DSM-IV diagnostic criteria and varied in phase of treatment; acute, stabilization and stable. The total of 150 volunteers aged 18 years and older were interviewed by psychiatric nurses using PASS8 before the patients were evaluated by psychiatrists with CGI-SCH. Data analysis was done by calculating Cronbach ‘s alpha coefficient, Pearson’s correlation coefficient (r), sensitivity, specificity, and likelihood ratio of cut-off point categorized level of symptoms severity according to assessment by using PASS8 Results: Out of the total of 150 participants, they were predominantly single male between the ages of 31 to 40 years old. More than half of volunteers had an income of less than 1,000 baht a month and lived in Ubon Ratchathani Province with their parents. After performing a statistical analysis, the Cronbach’s alpha indicated acceptable internal consistency. When comparing between PASS8‘s range of score categorized according to the severity of the symptoms and symptoms of patients with schizophrenia assessed by 2 psychiatrists using CGI-SCH, Pearson’s correlation coefficient (r) was 0.741 (p-value <0.001). This test showed that sensitivity, specificity, and likelihood ratio in mild severity level were 64%, 64% and 1.78 (0.38 to 0.85), respectively, in moderate severity level were 37%, 67 % and 1.11 (0.65 to 1.91), respectively, and in severe severity level were 75%, 93% and 11.25 (2.84 to 244.64), respectively. The mean duration of completing this rating scale was 6.0 minutes (SD 2.6). Minimum and maximum duration were 2.0 minutes and 14.0 minutes, respectively. Conclusion: PASS8 had acceptable internal consistency and statistic results indicated good correlation with CGI-SCH. It contained high sensitivity and specificity in separating schizophrenic patients with high severity and was adequate for evaluating patients with mild severity. It had low sensitivity in detection that was moderately severe. It used for evaluation of psychotic symptoms in patients with schizophrenia in short duration by trained primary/secondary health care provider.