ASSESSMENT OF EXTRAPYRAMIDAL SYMPTOMS DURING ACUTE NEUROLEPTIC TREATMENT

Background: Acute administration of traditional neuroleptic drugs is o ften accompanied by the emergence of extrapyramidal symptoms (EPS). Th e use of a standardized scale to measure EPS can assist the clinician in assessing the occurrence and severity of these adverse reactions. T he current work presents the interrater reliability and validity of th e Yale Extrapyramidal Symptom Scale (YESS)-an eight-item, easy-to-admi nister scale for assessing emergence, severity, and type of side effec ts that commonly occur during acute treatment. Method: Interrater reli ability (Study 1) and validity (Study 2) of the scale were studied usi ng two independent samples of acutely psychotic patients treated with neuroleptic drugs. Study 1: Interrater reliability was assessed by com paring the YESS ratings of two clinicians blind to the other's rating and to the patient's drug regimen and dose. Study 2: Validity was stud ied by examining whether YESS items correlated with other EPS measures (convergent validity) but not with psychotic symptoms that may be con fused with EPS (discriminant validity). Results: Interrater agreement between clinicians was good to excellent. YESS items correlated with a ssessments used to measure symptoms of Parkinson's disease and akathis ia and generally showed low nonsignificant correlations with ratings o f symptoms of psychosis. Conclusion: The current work presents a brief EPS scale for the assessment of commonly occurring neuroleptic-induce d extrapyramidal side effects. It was demonstrated that the YESS could be used reliably across clinician raters and that the YESS is a valid measure for assessing EPS during acute treatment.