Measurement of antipsychotic-induced side effects: support for the validity of a self-report (LUNSERS) versus structured interview (UKU) approach to measurement

A self-report measure of antipsychotic side effects (LUNSERS) was compared with that of an established semi-structured interview (UKU side effect rating scale). The validity and the ability of the LUNSERS to determine false positives by use of an internal 'red herring' subscale were assessed. 'Red herring' items are those which do not directly relate to known antipsychotic side effects. In an open study, 29 patients with schizophrenia and schizoaffective disorder from inpatient and outpatient settings within an Australian metropolitan mental health service were assessed for antipsychotic-induced side effects using both the LUNSERS and UKU. The LUNSERS and UKU were similar in their overall assessment of antipsychotic side effects (total score correlation of 0.58) and were correlated on a wide array of individual side effect items. Correlations between total scores and individual items were higher for those patients scoring low on the LUNSERS 'red herring' items compared with both those with high 'red herring' scores and the sample as a whole. Several LUNSERS items were identified as potentially problematic, requiring further explanation or supplementation with direct questioning. The 'red herring' scale appears to enable detection of patients that may be over-reporting symptomatology. The LUNSERS is a valuable self-report measure of antipsychotic side effects, particularly in cases where red herring scores are low.