Elsevier

Schizophrenia Research

Volume 79, Issue 1, 1 November 2005, Pages 85-93
Schizophrenia Research

The relationship between duration of untreated psychosis and outcome: An eight-year prospective study

https://doi.org/10.1016/j.schres.2005.05.024Get rights and content

Abstract

Longer duration of untreated psychosis (DUP) prior to the initiation of treatment has been found to predict poorer short-term clinical and functional outcomes in patients with first-episode psychosis (FEP). The extent to which the relationship between DUP and outcome is maintained in the medium-to-long term however remains unclear. We examined the influence of DUP on clinical and functional outcomes in a prospective, naturalistic study of 318 FEP patients followed up 8 years after initial treatment at a specialist early psychosis service. Quality of life, social and occupational functioning, positive and negative symptoms at 8 years were assessed using standardized instruments. Multiple linear regression analyses indicated that, after controlling for the effects of other factors, shorter DUP correlated moderately with decreased severity of positive symptoms, and enhanced social and occupational functioning and quality of life. There was no uniform point associated with medium-to-long term impairment, with some domains of outcome more sensitive to treatment delay than others. However a consistent finding was that outcomes for these domains were significantly worse when DUP exceeded 3 months. Among those with a schizophrenia-spectrum diagnosis, DUP exceeding 1 year was associated with poorer outcome. No association was found between DUP and negative symptoms in either diagnostic group. As with short-term prognosis, DUP appears to be an independent predictor of prognosis in the medium-to-long term. Results support the need for assertive early detection strategies to facilitate the timely delivery of effective intervention programs to those with emerging psychotic illness in order to reduce the risk of long term deleterious outcomes.

Introduction

There is evidence that the duration of untreated psychosis (DUP) correlates moderately with short-term symptomatic and functional outcomes in first-episode psychosis (FEP) (Carbone et al., 1999, Larsen et al., 1996, McGlashan, 1999) and that this association is independent of potential confounding factors, including premorbid functioning, gender, diagnosis and age at onset of symptoms (e.g., Bottlender et al., 2000, Drake et al., 2000, Haas et al., 1998, Harrigan et al., 2003, Larsen et al., 2000, Loebel et al., 1992). Nonetheless DUP is not universally accepted as a predictor of prognosis, with several studies failing to support an association (e.g., Craig et al., 2000, Ho et al., 2000).

To date, few prospective studies have examined this association over the longer term. Scully et al. (1997) reported a significant relationship between DUP and negative, but not positive symptoms, in a 12-year follow-up of 48 schizophrenia patients. Bottlender et al. (2003), in a 15-year follow-up of 58 patients with schizophrenia, reported reduced global functioning and more severe psychopathology amongst patients with a DUP exceeding 1 year compared to those with a DUP of less than 6 months. Although these results suggest that the influence of DUP does not diminish in the long term, clarification of the strength of this relationship and the domains of outcome affected is required in larger, representative samples.

This study examined whether DUP predicts clinical and functional outcomes, independent of potential confounding variables, in a large FEP cohort followed up 8 years after first psychiatric treatment. We further sought to determine whether a critical juncture exists at which delayed initial treatment leads to a decline in longer term functioning, and whether the effects of DUP observed at 12-month follow-up in this cohort (Harrigan et al., 2003) were maintained in the medium-to-long term.

Section snippets

Study design

The study involved a naturalistic, prospective, longitudinal, 8-year follow-up of a sample of 559 FEP patients treated at a specialist early psychosis service in Melbourne, Australia. Assessments were conducted at multiple time-points including: usually within the first few days following entry into treatment (index presentation; T1); at the time of symptom remission or stabilization (usually 8 weeks after index presentation; T2); 12 months after remission/stabilization (T3); and approximately

Characteristics of the sample

Analysis of baseline and early treatment characteristics of T4 interview completers (n = 318) and non-completers (n = 241) indicated that there were no statistically significant group differences on a range of demographic and clinical factors, including DUP (Table 1). The frequency of participants in each DUP category was: 0–7 days, N = 81 (25.5%, median = 5 days); 8–28 days, N = 63 (19.8%, median = 14 days); 29–90 days, N = 64 (20.1%, median = 58 days); 3 months–1 year, N = 74 (23.3%, median = 184 days); > 1 year,

Discussion

To our knowledge, this is the first prospective study to examine the relationship between DUP and outcome in a large representative sample of FEP patients over the medium-to-long term. The results demonstrate that, almost 8 years following index presentation, shorter DUP is significantly associated with decreased severity of positive symptoms, and enhanced social and occupational functioning and quality of life. These associations were evident among patients with a schizophrenia-spectrum

Acknowledgements

The authors thank Mr. Hok Pan Yuen for his statistical contribution to this paper. This study was partially supported by funding from the Colonial Foundation for the establishment of the ORYGEN Research Centre. These findings were presented at the 4th International Conference on Early Psychosis, Vancouver, Canada, 2004.

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