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The Relationship Between Course of Illness and β-Endorphin Plasma Levels in Patients with Schizophrenia

Authors Urban-Kowalczyk M, Kotlicka-Antczak M, Strzelecki D, Rudecka E, Śmigielski J

Received 30 July 2019

Accepted for publication 21 November 2019

Published 3 January 2020 Volume 2019:15 Pages 3609—3614


Checked for plagiarism Yes

Review by Single-blind

Peer reviewer comments 2

Editor who approved publication: Dr Roger Pinder

Małgorzata Urban-Kowalczyk,1 Magdalena Kotlicka-Antczak,1 Dominik Strzelecki,1 Ewa Rudecka,2,3 Janusz Śmigielski4

1Department of Affective and Psychotic Disorders, Medical University of Łódź, Łódź, Poland; 2Babiński Memorial Hospital in Łódź, Łódź, Poland; 3Faculty of Human Nutrition and Consumer Sciences, Warsaw University of Life Sciences SGGW, Warsaw, Poland; 4State High Vocational School in Konin, Konin, Poland

Correspondence: Małgorzata Urban-Kowalczyk
Department of Affective and Psychotic Disorders, Medical University of Łódź, Czechosłowacka 8/10, Lodz 92-216, Poland
Tel +48 42 675 73 71
Fax +48 42 675 74 03

Objective: Extensive investigations have been conducted into predictors of schizophrenia outcome. The heterogeneity of the illness implies that many factors should be taken into account. Some studies have reported the relationship between increased β-endorphin concentration and predominant negative symptoms.
Methods: We included 77 outpatients with schizophrenia and 74 healthy controls. Data referring to duration and course of illness, hospitalization number and treatment were collected on the basis of clinical interviews and medical documentation analysis. The β-endorphin concentrations were assessed once in all participants, at the onset of the study.
Results: A chronic course of illness was found in 44 of the 77 schizophrenics. Patients with schizophrenia, especially those with a chronic course of illness, revealed significantly higher β-endorphin concentrations than those with an episodic course and controls (mean 29.70 vs 19.86 pmol/L; p=0.0001). Increased levels of β-endorphin were related to longer duration of illness (R=0.294, p=0.009) and frequent psychiatric hospitalization (R=0.346, p=–0.002).
Conclusion: Endorphins may be potential biological predictors of persistent negative symptoms and final outcome in schizophrenia.

Keywords: β-endorphin, dopamine, opioid peptides, schizophrenia

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