Differential impacts of duration of untreated psychosis (DUP) on cognitive function in first-episode schizophrenia according to mode of onset.
BACKGROUND
The mode of onset and the course of schizophrenia illness exhibit substantial individual variations. Previous studies have pointed out that the mode of onset affects the duration of untreated psychosis (DUP) and clinical outcomes, such as cognitive and social functioning. This study attempted to clarify the association between the DUP and clinical features, taking the different modes of onset into consideration, in a prospective longitudinal study examining patients with first-episode schizophrenia.


METHODS
This study was conducted in six areas of Japan. Patients with first-episode schizophrenia were followed for over 18 months. Cognitive function, psychopathology, and social functioning were assessed at baseline and at 6, 12, and 18-month follow-up points.


RESULTS
We identified 168 patients and sufficient information was available to determine the DUP and the mode of onset for 156 patients (92.9%): 79 had an acute onset, and 77 had an insidious onset. The DUP was significantly associated with quality of life (QOL), social functioning, and cognitive function at most of the follow-up points in the insidious-onset group. The DUP and negative symptoms at baseline were significant predictors of cognitive function at the 18-month follow-up in the insidious-onset group.


CONCLUSIONS
The present results further support the hypothesis that the DUP affects QOL, social functioning, and cognitive function over the course of illness, especially in patients with an insidious onset. Effective strategies for detecting and caring for individuals with insidious onset early during the course of schizophrenia will be essential for achieving a full patient recovery.
Department of Social Medicine, Toho University School of Medicine, Tokyo, Japan.
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Ito
Department of Neuropsychiatry, Toho University School of Medicine, Tokyo, Japan. Electronic address: takahiro.nemoto@med.toho-u.ac.jp.
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T
Nemoto
Department of Neuropsychiatry, Toho University School of Medicine, Tokyo, Japan.
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Tsujino
Department of Psychiatry, Tohoku University Graduate School of Medicine, Sendai, Japan.
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Ohmuro
Department of Psychiatry, Tohoku University Graduate School of Medicine, Sendai, Japan.
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Matsumoto
Department of Psychiatry, Tohoku University Graduate School of Medicine, Sendai, Japan.
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Matsuoka
Department of Neuropsychiatry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
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Tanaka
Department of Neuropsychiatry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
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Nishiyama
Department of Neuropsychiatry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
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Suzuki
Department of Neuropsychiatry, Unit of Translational Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
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Kinoshita
Department of Neuropsychiatry, Unit of Translational Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
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Ozawa
Department of Neuropsychiatry, Kochi Medical School, Kochi University, Kochi, Japan.
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Fujita
Department of Neuropsychiatry, Kochi Medical School, Kochi University, Kochi, Japan.
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Shimodera
Department of Psychiatry, Nara Medical University, Nara, Japan.
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Kishimoto
Department of Social Medicine, Toho University School of Medicine, Tokyo, Japan.
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Matsumoto
Department of Social Medicine, Toho University School of Medicine, Tokyo, Japan.
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T
Hasegawa
Department of Neuropsychiatry, Toho University School of Medicine, Tokyo, Japan.
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Mizuno
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D003071:Cognition; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D017063:Outcome Assessment, Health Care; D011446:Prospective Studies; D011580:Psychological Techniques; D011618:Psychotic Disorders / Q000628:therapy; D011788:Quality of Life; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D012565:Schizophrenic Psychology; D066107:Social Skills; D061665:Time-to-Treatment
D014150:Antipsychotic Agents
Cognitive function; Duration of untreated psychosis (DUP); First-episode; Mode of onset; Prospective follow-up; Schizophrenia