Hostname: page-component-7dd5485656-wxk4p Total loading time: 0 Render date: 2025-10-30T20:04:53.390Z Has data issue: false hasContentIssue false
  • English
  • Français

Modeling psychological function in patients with schizophrenia with the PANSS: an international multi-center study

Published online by Cambridge University Press:  15 April 2020

Konstantinos N. Fountoulakis Open the ORCID record for Konstantinos N. Fountoulakis [Opens in a new window] ,
Elena Dragioti ,
Antonis T. Theofilidis ,
Tobias Wiklund ,
Xenofon Atmatzidis ,
Ioannis Nimatoudis ,
Erik Thys ,
Martien Wampers ,
Luchezar Hranov  and
Trayana Hristova
...Show all authors
Konstantinos N. Fountoulakis*
Affiliation:
3rd Department of Psychiatry, Faculty of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
Elena Dragioti
Affiliation:
Department of Medical and Health Sciences (IMH), Faculty of Health Sciences, Linköping University, Linköping, Sweden Hallunda Psychiatric Outpatient Clinic, Stockholm Psychiatric Southwest Clinic, Karolinska Huddinge University Hospital, Huddinge, Sweden
Antonis T. Theofilidis
Affiliation:
3rd Department of Psychiatry, Faculty of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
Tobias Wiklund
Affiliation:
Department of Medical and Health Sciences (IMH), Faculty of Health Sciences, Linköping University, Linköping, Sweden Hallunda Psychiatric Outpatient Clinic, Stockholm Psychiatric Southwest Clinic, Karolinska Huddinge University Hospital, Huddinge, Sweden
Xenofon Atmatzidis
Affiliation:
Department of Medical and Health Sciences (IMH), Faculty of Health Sciences, Linköping University, Linköping, Sweden Hallunda Psychiatric Outpatient Clinic, Stockholm Psychiatric Southwest Clinic, Karolinska Huddinge University Hospital, Huddinge, Sweden
Ioannis Nimatoudis
Affiliation:
3rd Department of Psychiatry, Faculty of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
Erik Thys
Affiliation:
University Psychiatric Center, Katholieke Universiteit Leuven, Kortenberg, Belgium
Martien Wampers
Affiliation:
University Psychiatric Center, Katholieke Universiteit Leuven, Kortenberg, Belgium Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
Luchezar Hranov
Affiliation:
University Multiprofile Hospital for Active Treatment in Neurology and Psychiatry "Sveti Naum", Sofia, Bulgaria
Trayana Hristova
Affiliation:
University Multiprofile Hospital for Active Treatment in Neurology and Psychiatry "Sveti Naum", Sofia, Bulgaria
Daniil Aptalidis
Affiliation:
University Multiprofile Hospital for Active Treatment in Neurology and Psychiatry "Sveti Naum", Sofia, Bulgaria
Roumen Milev
Affiliation:
Department of Psychiatry, Queen’s University, Providence Care Hospital, Kingston, Ontario, Canada
Felicia Iftene
Affiliation:
Department of Psychiatry, Queen’s University, Providence Care Hospital, Kingston, Ontario, Canada
Filip Spaniel
Affiliation:
National Institute of Mental Health, Klecany, Czech Republic
Pavel Knytl
Affiliation:
National Institute of Mental Health, Klecany, Czech Republic
Petra Furstova
Affiliation:
National Institute of Mental Health, Klecany, Czech Republic
Tiina From
Affiliation:
Department of Psychiatry, University of Turku, Turku, Finland
Henry Karlsson
Affiliation:
Department of Psychiatry, University of Turku, Turku, Finland
Maija Walta
Affiliation:
Department of Psychiatry, University of Turku, Turku, Finland
Raimo K.R. Salokangas
Affiliation:
Department of Psychiatry, University of Turku, Turku, Finland
Jean-Michel Azorin
Affiliation:
Department of Psychiatry, Sainte Marguerite University Hospital, Marseille, France Timone Institute of Neuroscience, Marseille, France
Justine Bouniard
Affiliation:
Department of Psychiatry, Sainte Marguerite University Hospital, Marseille, France Timone Institute of Neuroscience, Marseille, France
Julie Montant
Affiliation:
Department of Psychiatry, Sainte Marguerite University Hospital, Marseille, France Timone Institute of Neuroscience, Marseille, France
Georg Juckel
Affiliation:
Department of Psychiatry, Ruhr University Bochum, Bochum, Germany
Ida S. Haussleiter
Affiliation:
Department of Psychiatry, Ruhr University Bochum, Bochum, Germany
Athanasios Douzenis
Affiliation:
2nd Department of Psychiatry, National and Kapodistrian University of Athens, Athens, Greece
Ioannis Michopoulos
Affiliation:
2nd Department of Psychiatry, National and Kapodistrian University of Athens, Athens, Greece
Panagiotis Ferentinos
Affiliation:
2nd Department of Psychiatry, National and Kapodistrian University of Athens, Athens, Greece
Nikolaos Smyrnis
Affiliation:
Department of Psychiatry, National and Kapodistrian University of Athens School of Medicine, Eginition Hospital, Athens, Greece
Leonidas Mantonakis
Affiliation:
Department of Psychiatry, National and Kapodistrian University of Athens School of Medicine, Eginition Hospital, Athens, Greece
Zsófia Nemes
Affiliation:
Nyírő Gyula Hospital, Budapest, Hungary
Xenia Gonda
Affiliation:
Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest, Hungary
Dora Vajda
Affiliation:
Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest, Hungary
Anita Juhasz
Affiliation:
Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest, Hungary
Amresh Shrivastava
Affiliation:
Western University, London, Ontario, Canada
John Waddington
Affiliation:
Department of Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
Maurizio Pompili
Affiliation:
Department of Neurosciences, Mental Health and Sensory Organs, Suicide Prevention Center, Sant’Andrea Hospital, Sapienza University of Rome, Rome, Italy
Anna Comparelli
Affiliation:
Department of Neurosciences, Mental Health and Sensory Organs, Suicide Prevention Center, Sant’Andrea Hospital, Sapienza University of Rome, Rome, Italy
Valentina Corigliano
Affiliation:
Department of Neurosciences, Mental Health and Sensory Organs, Suicide Prevention Center, Sant’Andrea Hospital, Sapienza University of Rome, Rome, Italy
Elmars Rancans
Affiliation:
Department of Psychiatry and Narcology, Riga Stradins University, Riga, Latvia
Alvydas Navickas
Affiliation:
Department of Clinic of Psychiatric, Faculty of Medicine, Vilnius University, Vilnius, Lithuania Department of Psychosocial Rehabilitation, Vilnius Mental Health Center, Vilnius, Lithuania Department for Psychosis Treatment, Vilnius Mental Health Center, Vilnius, Lithuania
Jan Hilbig
Affiliation:
Department of Clinic of Psychiatric, Faculty of Medicine, Vilnius University, Vilnius, Lithuania Department of Psychosocial Rehabilitation, Vilnius Mental Health Center, Vilnius, Lithuania Department for Psychosis Treatment, Vilnius Mental Health Center, Vilnius, Lithuania
Laurynas Bukelskis
Affiliation:
Department of Clinic of Psychiatric, Faculty of Medicine, Vilnius University, Vilnius, Lithuania Department of Psychosocial Rehabilitation, Vilnius Mental Health Center, Vilnius, Lithuania Department for Psychosis Treatment, Vilnius Mental Health Center, Vilnius, Lithuania
Lidija I. Stevovic
Affiliation:
Clinical Department of Psychiatry, Clinical Centre of Montenegro, Podgorica, Montenegro Department of Psychiatry, School of Medicine, University of Montenegro, Podgorica, Montenegro Clinical Department of Neurology, Clinical Centre of Montenegro, Podgorica, Montenegro
Sanja Vodopic
Affiliation:
Clinical Department of Psychiatry, Clinical Centre of Montenegro, Podgorica, Montenegro Department of Psychiatry, School of Medicine, University of Montenegro, Podgorica, Montenegro Clinical Department of Neurology, Clinical Centre of Montenegro, Podgorica, Montenegro
Oluyomi Esan
Affiliation:
Department of Psychiatry, College of Medicine, University of Ibadan, Ibadan, Nigeria
Oluremi Oladele
Affiliation:
Department of Psychiatry, College of Medicine, University of Ibadan, Ibadan, Nigeria
Christopher Osunbote
Affiliation:
Department of Psychiatry, College of Medicine, University of Ibadan, Ibadan, Nigeria
Janusz K. Rybakowski
Affiliation:
Department of Adult Psychiatry, Poznan University of Medical Sciences, Poznan, Poland
Pawel Wojciak
Affiliation:
Department of Adult Psychiatry, Poznan University of Medical Sciences, Poznan, Poland
Klaudia Domowicz
Affiliation:
Department of Adult Psychiatry, Poznan University of Medical Sciences, Poznan, Poland
Maria L. Figueira
Affiliation:
Department of Psychiatry and Mental Health, Santa Maria University Hospital, Lisbon, Portugal
Ludgero Linhares
Affiliation:
Department of Psychiatry and Mental Health, Santa Maria University Hospital, Lisbon, Portugal
Joana Crawford
Affiliation:
Department of Psychiatry and Mental Health, Santa Maria University Hospital, Lisbon, Portugal
Anca-Livia Panfil
Affiliation:
University of Medicine and Pharmacy of Târgu Mures, Târgu Mures, Romania
Daria Smirnova
Affiliation:
Department of Psychiatry, Samara Psychiatric Hospital, Inpatient Unit, Samara State Medical University, Samara, Russia
Olga Izmailova
Affiliation:
Department of Psychiatry, Samara Psychiatric Hospital, Inpatient Unit, Samara State Medical University, Samara, Russia
Dusica Lecic-Tosevski
Affiliation:
Institute of Mental Health, Belgrade, Serbia Serbian Academy of Sciences and Arts, Belgrade, Serbia
Henk Temmingh
Affiliation:
Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
Fleur Howells
Affiliation:
Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
Julio Bobes
Affiliation:
Department of Psychiatry, University of Oviedo and Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Oviedo, Spain
Maria P. Garcia-Portilla
Affiliation:
Department of Psychiatry, University of Oviedo and Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Oviedo, Spain
Leticia García-Alvarez
Affiliation:
Department of Psychiatry, University of Oviedo and Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Oviedo, Spain
Gamze Erzin
Affiliation:
Psychiatry Department, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
Hasan Karadağ
Affiliation:
Psychiatry Department, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
Avinash De Sousa
Affiliation:
Department of Psychiatry, Lokmanya Tilak Municipal Medical College, Mumbai, India
Anuja Bendre
Affiliation:
Department of Psychiatry, Lokmanya Tilak Municipal Medical College, Mumbai, India
Cyril Hoschl
Affiliation:
National Institute of Mental Health, Klecany, Czech Republic
Cristina Bredicean
Affiliation:
University of Medicine and Pharmacy of Timisoara, Timisoara, Romania
Ion Papava
Affiliation:
University of Medicine and Pharmacy of Timisoara, Timisoara, Romania
Olivera Vukovic
Affiliation:
Institute of Mental Health, School of Medicine, University of Belgrade, Belgrade, Serbia
Bojana Pejuskovic
Affiliation:
Department of Psychiatry, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
Vincent Russell
Affiliation:
Department of Psychiatry, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
Loukas Athanasiadis
Affiliation:
1st Department of Psychiatry, Faculty of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
Anastasia Konsta
Affiliation:
1st Department of Psychiatry, Faculty of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
Dan Stein
Affiliation:
MRC Unit on Risk and Resilience in Mental Disorders, Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
Michael Berk
Affiliation:
IMPACT Strategic Research Centre, School of Medicine, Barwon Health, Deakin University, Geelong, Australia Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia Centre for Youth Mental Health, The Florey Institute for Neuroscience and Mental Health, Parkville, Victoria, Australia Department of Psychiatry, University of Melbourne, Parkville, Victoria, Australia
Olivia Dean
Affiliation:
IMPACT Strategic Research Centre, School of Medicine, Barwon Health, Deakin University, Geelong, Australia Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia Centre for Youth Mental Health, The Florey Institute for Neuroscience and Mental Health, Parkville, Victoria, Australia Department of Psychiatry, University of Melbourne, Parkville, Victoria, Australia
Rajiv Tandon
Affiliation:
Department of Psychiatry, University of Florida, Gainesville, Florida, USA
Siegfried Kasper
Affiliation:
Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
Marc De Hert
Affiliation:
University Psychiatric Center, Katholieke Universiteit Leuven, Kortenberg, Belgium Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium Antwerp Health Law and Ethics Chair—AHLEC University, Antwerpen, Belgium
*
Author for correspondence: Konstantinos N. Fountoulakis, Email: kfount@med.auth.gr
Get access Rights & Permissions [Opens in a new window]

Abstract

Background

The aim of the current study was to explore the changing interrelationships among clinical variables through the stages of schizophrenia in order to assemble a comprehensive and meaningful disease model.

Methods

Twenty-nine centers from 25 countries participated and included 2358 patients aged 37.21 ± 11.87 years with schizophrenia. Multiple linear regression analysis and visual inspection of plots were performed.

Results

The results suggest that with progression stages, there are changing correlations among Positive and Negative Syndrome Scale factors at each stage and each factor correlates with all the others in that particular stage, in which this factor is dominant. This internal structure further supports the validity of an already proposed four stages model, with positive symptoms dominating the first stage, excitement/hostility the second, depression the third, and neurocognitive decline the last stage.

Conclusions

The current study investigated the mental organization and functioning in patients with schizophrenia in relation to different stages of illness progression. It revealed two distinct “cores” of schizophrenia, the “Positive” and the “Negative,” while neurocognitive decline escalates during the later stages. Future research should focus on the therapeutic implications of such a model. Stopping the progress of the illness could demand to stop the succession of stages. This could be achieved not only by both halting the triggering effect of positive and negative symptoms, but also by stopping the sensitization effect on the neural pathways responsible for the development of hostility, excitement, anxiety, and depression as well as the deleterious effect on neural networks responsible for neurocognition.

Keywords

Schizophreniamodelstaginglong-term courseoutcome

Information

Type
Original Research
Information
CNS Spectrums , Volume 26 , Issue 3 , June 2021 , pp. 290 - 298
Copyright
© Cambridge University Press 2020

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

Baruch, I, Hemsley, DR, Gray, JA. Differential performance of acute and chronic schizophrenics in a latent inhibition task. J Nerv Ment Dis. 1988;176(10):598–606.CrossRefGoogle Scholar
Pfohl, B, Winokur, G. The evolution of symptoms in institutionalized hebephrenic/catatonic schizophrenics. Br J Psychiatry J Ment Sci. 1982;141:567–572.CrossRefGoogle ScholarPubMed
Liddle, PF. The symptoms of chronic schizophrenia. A re-examination of the positive-negative dichotomy. Br J Psychiatry J Ment Sci. 1987;151:145–151.CrossRefGoogle ScholarPubMed
Stein, K, Broome, MR. Neuroprogression in schizophrenia: pathways and underpinning clinical staging and therapeutic corollaries. Aust N Z J Psychiatry. 2015;49(2):183–184.CrossRefGoogle ScholarPubMed
Davis, J, Moylan, S, Harvey, BH, Maes, M, Berk, M. Neuroprogression in schizophrenia: pathways underpinning clinical staging and therapeutic corollaries. Aust N Z J Psychiatry. 2014;48(6):512–529.CrossRefGoogle ScholarPubMed
Lieberman, JA, Sheitman, BB, Kinon, BJ. Neurochemical sensitization in the pathophysiology of schizophrenia: deficits and dysfunction in neuronal regulation and plasticity. Neuropsychopharmacology. 1997;17(4):205–229.CrossRefGoogle ScholarPubMed
Fountoulakis, KN, Dragioti, E, Theofilidis, AT, et al. Staging of schizophrenia with the use of PANSS: an International Multi-Center Study. Int J Neuropsychopharmacol. 2019;22(11):681–697.CrossRefGoogle ScholarPubMed
APA. Diagnostic and Statistical Manual of Mental Disorders: DSM-5. Washington, DC: American Psychiatric Association; 2013.Google Scholar
APA. Diagnostic and Statistical Manual of Mental Disorders: Fourth Edition Text Revision DSM-IV-TR. Washington, DC: American Psychiatric Association; 2000.Google Scholar
Kay, SR. Positive-negative symptom assessment in schizophrenia: psychometric issues and scale comparison. Psychiatr Quarter. 1990;61(3):163–178.CrossRefGoogle ScholarPubMed
Kay, SR, Fiszbein, A, Opler, LA. The positive and negative syndrome scale (PANSS) for schizophrenia. Schizophr Bull. 1987;13(2):261–276.CrossRefGoogle Scholar
Kay, SR, Opler, LA, Lindenmayer, JP. Reliability and validity of the positive and negative syndrome scale for schizophrenics. Psychiatry Res. 1988;23(1):99–110.CrossRefGoogle ScholarPubMed
Kay, SR, Sandyk, R. Experimental models of schizophrenia. Int J Neurosci. 1991;58(1–2):69–82.CrossRefGoogle ScholarPubMed
Kay, SR, Sevy, S. Pyramidical model of schizophrenia. Schizophr Bull. 1990;16(3):537–545.CrossRefGoogle ScholarPubMed
Millan, MJ, Andrieux, A, Bartzokis, G, et al. Altering the course of schizophrenia: progress and perspectives. Nat Rev Drug Discov. 2016;15(7):485–515.CrossRefGoogle Scholar
Andreasen, NC, Olsen, S. Negative v positive schizophrenia. Definition and validation. Arch Gen Psychiatry. 1982;39(7):789–794.CrossRefGoogle Scholar
Crow, TJ. The two-syndrome concept: origins and current status. Schizophr Bull. 1985;11(3):471–486.CrossRefGoogle ScholarPubMed
Andreasen, NC, Paradiso, S, O’Leary, DS. "Cognitive dysmetria" as an integrative theory of schizophrenia: a dysfunction in cortical-subcortical-cerebellar circuitry? Schizophr Bull. 1998;24(2):203–218.CrossRefGoogle ScholarPubMed
Hemsley, DR. The development of a cognitive model of schizophrenia: placing it in context. Neurosci Biobehav Rev. 2005;29(6):977–988.CrossRefGoogle ScholarPubMed
de Lafuente, V, Romo, R. Dopamine neurons code subjective sensory experience and uncertainty of perceptual decisions. Proc Natl Acad Sci U S A. 2011;108(49):19767–19771.CrossRefGoogle ScholarPubMed
de Lafuente, V, Romo, R. Dopaminergic activity coincides with stimulus detection by the frontal lobe. Neuroscience. 2012;218:181–184.CrossRefGoogle ScholarPubMed
Beck, AT, Rector, NA. Cognitive approaches to schizophrenia: theory and therapy. Ann Rev Clin Psychol. 2005;1:577–606.CrossRefGoogle ScholarPubMed
Howes, OD, Murray, RM. Schizophrenia: an integrated sociodevelopmental-cognitive model. Lancet. 2014;383(9929):1677–1687.CrossRefGoogle ScholarPubMed
Davis, J, Eyre, H, Jacka, FN, et al. A review of vulnerability and risks for schizophrenia: beyond the two hit hypothesis. Neurosci Biobehav Rev. 2016;65:185–194.CrossRefGoogle ScholarPubMed
Ciompi, L. The natural history of schizophrenia in the long term. Br J Psychiatry J Ment Sci. 1980;136(5):413–420.CrossRefGoogle ScholarPubMed
Davidson, M, Harvey, PD, Haroutunian, V, et al. Symptom severity and cognitive impairment in elderly schizophrenic patients. Schizophr Res. 1993;9(2–3):97.CrossRefGoogle Scholar
Miller, R. Schizophrenia as a progressive disorder – relations to Eeg, Ct, neuropathological and other evidence. Prog Neurobiol. 1989;33(1):17–44.CrossRefGoogle ScholarPubMed
Goldberg, TE, Gold, JM, Greenberg, R, et al. Contrasts between patients with affective disorders and patients with schizophrenia on a neuropsychological test battery. Am J Psychiatry. 1993;150(9):1355–1362.Google ScholarPubMed
McKenna, PJ, Lund, CE, Mortimer, AM. Negative symptoms: relationship to other schizophrenic symptom classes. Br J Psychiatry. 1989;155(7):104–107.CrossRefGoogle Scholar
Goldberg, TE, Ragland, JD, Torrey, EF, Gold, JM, Bigelow, LB, Weinberger, DR. Neuropsychological assessment of monozygotic twins discordant for schizophrenia. Arch Gen Psychiatry. 1990;47(11):1066–1072.CrossRefGoogle Scholar
Goldberg, TE, Torrey, EF, Gold, JM, et al. Genetic risk of neuropsychological impairment in schizophrenia: a study of monozygotic twins discordant and concordant for the disorder. Schizophr Res. 1995;17(1):77–84.CrossRefGoogle ScholarPubMed
Suddath, RL, Christison, GW, Torrey, EF, Casanova, MF, Weinberger, DR. Anatomical abnormalities in the brains of monozygotic twins discordant for schizophrenia. N Engl J Med. 1990;322(12):789–794.CrossRefGoogle Scholar
Kaprinis, GS, Fountoulakis, KN, Kaprinis, SG. Arguments against the cognitive dysmetria hypothesis of schizophrenia. Percept Mot Skills. 2002;94(3 Pt 1):975–984.CrossRefGoogle ScholarPubMed
Goldberg, TE, Hyde, TM, Kleinman, JE, Weinberger, DR. Course of schizophrenia: neuropsychological evidence for a static encephalopathy. Schizophr Bull. 1993;19(4):797–804.CrossRefGoogle ScholarPubMed
Hoff, AL, Riordan, H, O’Donnell, DW, Morris, L, DeLisi, LE. Neuropsychological functioning of first-episode schizophreniform patients. Am J Psychiatry. 1992;149(7):898–903.Google ScholarPubMed
Weinberger, DR. Implications of normal brain development for the pathogenesis of schizophrenia. Arch Gen Psychiatry. 1987;44(7):660–669.CrossRefGoogle ScholarPubMed
Picchioni, M, Harris, S, Reichenberg, A, Fahy, T, Murphy, D. A neuro-psychological model of violence propensity in schizophrenia. Eur Psychiatry. 2016;33:S573.Google Scholar
Lieberman, JA, Perkins, D, Belger, A, et al. The early stages of schizophrenia: speculations on pathogenesis, pathophysiology, and therapeutic approaches. Biol Psychiatry. 2001;50(11):884–897.CrossRefGoogle ScholarPubMed
Mohler, H, Rudolph, U. Disinhibition, an emerging pharmacology of learning and memory. F1000Res. 2017;6Google ScholarPubMed
Goldberg, TE, Weinberger, DR, Berman, KF, Pliskin, NH, Podd, MH. Further evidence for dementia of the prefrontal type in schizophrenia? A controlled study of teaching the Wisconsin Card Sorting Test. Arch Gen Psychiatry. 1987;44(11):1008–1014.CrossRefGoogle ScholarPubMed
Wunderink, L, Nieboer, RM, Wiersma, D, Sytema, S, Nienhuis, FJ. Recovery in remitted first-episode psychosis at 7 years of follow-up of an early dose reduction/discontinuation or maintenance treatment strategy: long-term follow-up of a 2-year randomized clinical trial. JAMA Psychiatry. 2013;70(9):913–920.CrossRefGoogle ScholarPubMed
Andreasen, NC, Liu, D, Ziebell, S, Vora, A, Ho, BC. Relapse duration, treatment intensity, and brain tissue loss in schizophrenia: a prospective longitudinal MRI study. Am J Psychiatry. 2013;170(6):609–615.CrossRefGoogle ScholarPubMed
Lorr, M, Mc, ND, Klett, CJ, Lasky, JJ. Evidence of ten psychotic syndromes. J Consult Psychol. 1962;26:185–189.CrossRefGoogle ScholarPubMed
Kitamura, T, Okazaki, Y, Fujinawa, A, Yoshino, M, Kasahara, Y. Symptoms of psychoses. A factor-analytic study. Br J Psychiatry J Ment Sci. 1995;166(2):236–240.CrossRefGoogle ScholarPubMed
Van Os, J, Gilvarry, C, Bale, R, et al. A comparison of the utility of dimensional and categorical representations of psychosis. UK700 Group. Psychol Med. 1999;29(3):595–606.CrossRefGoogle ScholarPubMed
Peralta, V, Cuesta, MJ. Dimensional structure of psychotic symptoms: an item-level analysis of SAPS and SANS symptoms in psychotic disorders. Schizophr Res. 1999;38(1):13–26.CrossRefGoogle ScholarPubMed
Fountoulakis, KN, Popovic, D, Mosheva, M, Siamouli, M, Moutou, K, Gonda, X. Mood symptoms in stabilized patients with schizophrenia: a bipolar type with predominant psychotic features? Psychiatr Danub. 2017;29(2):148–154.CrossRefGoogle ScholarPubMed
van Os, J, Fahy, TA, Jones, P, et al. Psychopathological syndromes in the functional psychoses: associations with course and outcome. Psychol Med. 1996;26(1):161–176.CrossRefGoogle ScholarPubMed
McGorry, PD, Bell, RC, Dudgeon, PL, Jackson, HJ. The dimensional structure of first episode psychosis: an exploratory factor analysis. Psychol Med. 1998;28(4):935–947.CrossRefGoogle ScholarPubMed
Willem Van der Does, AJ, Dingemans, PM, Linszen, DH, Nugter, MA, Scholte, WF. Dimensions and subtypes of recent-onset schizophrenia. A longitudinal analysis. J Nerv Ment Dis. 1995;183(11):681–687.CrossRefGoogle ScholarPubMed
Salokangas, RK. Structure of schizophrenic symptomatology and its changes over time: prospective factor-analytical study. Acta Psychiatr Scand. 1997;95(1):32–39.CrossRefGoogle ScholarPubMed
Ran, MS, Weng, X, Chan, CL, et al. Different outcomes of never-treated and treated patients with schizophrenia: 14-year follow-up study in rural China. Br J Psychiatry J Ment Sci. 2015;207(6):495–500.CrossRefGoogle ScholarPubMed