RESUMEN
BACKGROUND: Anxiety disorders are some of the most prevalent psychiatric disorders, have early onset, are chronic and can cause functional impairment. It is, therefore, crucial to establish an accurate diagnosis for treatment and research purposes. OBJECTIVE: To test the validity and reliability of the W.H.O. Schedules for Clinical Assessment in Neuropsychiatry (SCAN Thai Version): Anxiety Disorders Section. MATERIAL AND METHOD: The linguistic clarity of the psychiatric schedules for Thais was tested by psychiatrists from the country's four regions. The psychiatrists were competent in the use of the schedules and their underlying objectives. Then between October 2004 and August 2005, Reliability of SCAN: anxiety disorder section was tested among 30 participants, including patients with anxiety disorders and normal volunteers. RESULTS: Based on reactions from Thais and consultations from competent psychiatrists, content validity was established. The duration of interviews for anxiety disorders section averaged 45.1 min (SD = 13.5). The reliability determined by Cohen's kappa coefficient for the 83 items that related to anxiety disorders in the SCAN were in Section 3, 4, 5. This overall inter-rater reliability was 0.79 (SD = 0.22), which were in substantial level of agreement. The overall intra-rater reliability was rated by the same psychiatrist 2 weeks apart. The result was 0.84 (SD = 0.21), which was near perfect agreement. There were three items (3.6%) of fair agreement and five items (6%) of moderate agreement that were caused from discrepancy of item definitions and the subjectivity of raters. CONCLUSION: The Anxiety Disorders Sections of the WHO Schedules for Clinical Assessment in Neuropsychiatry (SCAN Thai Version) were an effective tool for assessing symptoms of anxiety disorders among Thais.