Enduring negative or deficit symptoms in first-episode psychosis: Comparison of 3 methods using follow-up data

Abstract

Targeted early intervention in the treatment of enduring positive and negative symptoms in first-episode psychosis is contingent on adequate case-identification procedures. Three methods of determining enduring negative symptoms in a sample of 227 first-episode patients assessed at 3 time points over a 12 month period are described: (a) global scores ofGE 3 on at least two SANS sub-scales of affective flattening, alogia, avolition/apathy, anhedonia/asociality across all follow-ups; (b) previous strategy with cases excluded if evidence of significant anxiety or depression. high neurolept ic dose, Parkinsonian side-effects, severe illicit drug use, or prolonged positive symptoms; and (c) a variation of Mueser et at 's (1991) method using the QLS (LE 2 on items 13, 15, 16) and the SANS (GE 4 on items 8, 13, 22) with two or more symptoms required at the latter two follow-up points. Method (a) identified 20 individuals (8.8%) as cases. With the application of exclusion criteria 12 (5.3%) cases remained. Mueser's method identified 47 cases (21%). Differences between the enduring deficit versus nondeficit individuals on the QLS, GAF and PAS were highly significant for all methods. The prevalence of enduring negative symptoms in this first-episode sample differs markedly according to the time frames adopted, the cut-off scores on the defining scales, and whether exclusion criteria are applied. Incorporation of clinician and patient interview schedules, such as the SDS, with prospective methods may improve operationalisation of the deficit concept.