This study systematically compared duration of untreated illness (DUI) with duration of untreated psychosis (DUP) in prediction of impairment at first-episode psychosis and investigated the extent to which these relationships are influenced by premorbid features. The Cavan-Monaghan First Episode Psychosis Study ascertained cases of first-episode psychosis in rural Ireland via all routes to care with limited variations in socioeconomic milieu. Cases were evaluated for DUI and DUP and assessed clinically for psychopathology, neuropsychology, neurology, insight and quality of life, together with premorbid features. Analyses then determined prediction of clinical assessments by DUI versus DUP. The study population consisted of 163 cases of first episode psychosis, among which 74 had a schizophrenia spectrum disorder. Shorter DUI but not DUP predicted less severe positive and general symptoms, while shorter DUP and particularly DUI predicted less severe negative symptoms; neither shorter DUP nor shorter DUI predicted less severe cognitive impairment or fewer neurological soft signs; shorter DUP and DUI predicted increased quality of life; shorter DUI but not DUP predicted greater insight. Only prediction of quality of life was weakened by consideration of premorbid features. Results were generally similar across the two diagnostic groupings. The present findings systematically delineate associations with DUI versus DUP across domains of impairment in first episode psychosis. They suggest that DUI may reflect a more insidious process than DUP and that reduction in DUI may be associated with more consistent and broader diminutions in impairment than for DUP.
Copyright © 2021. Published by Elsevier B.V.