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