Pharmacopsychiatry 2016; 49(04): 162-169
DOI: 10.1055/s-0042-101557
Original Paper
© Georg Thieme Verlag KG Stuttgart · New York

Duloxetine Add-On to Risperidone for Treatment of Negative Symptoms in Patients with Stable Schizophrenia: Randomized Double-Blind Placebo-Controlled Study

M.-R. Nikbakhat*
1   Department of Pharmacology, School of Medicine, Yasuj University of Medical Sciences, Yasuj, Iran
,
S. Arabzadeh*
2   Psychiatric Research Center, Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran
,
A. Zeinoddini*
2   Psychiatric Research Center, Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran
,
Z. Khalili
2   Psychiatric Research Center, Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran
,
F. Rezaei
3   Qods Hospital, Kurdistan University of Medical Sciences, Sanandaj, Iran
,
P. Mohammadinejad
2   Psychiatric Research Center, Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran
,
A. Ghaleiha
4   Research Center for Behavioral Disorders and Substance Abuse, Hamadan University of Medical Sciences, Hamadan, Iran
,
S. Akhondzadeh
2   Psychiatric Research Center, Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran
› Author Affiliations
Further Information

Publication History

received 13 October 2015
revised 27 December 2015

accepted 15 January 2016

Publication Date:
22 February 2016 (online)

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Abstract

Introduction: Although the pathogenesis of symptoms of schizophrenia is largely unknown, a variety of neurotransmitters are implicated, including serotonin and norepinephrine. Here we investigate the effectiveness of duloxetine as a serotonin-norepinephrine inhibitor in the treatment of negative symptoms.

Methods: We performed a double-blind clinical trial on 64 patients with stable schizophrenia and no prominent symptoms of depression. Patients received risperidone (up to 6 mg/day) plus either duloxetine (60 mg/day) or placebo. Psychotic symptoms were assessed by the Positive and Negative Syndrome Scale (PANSS) at the onset of the trial, and at 2, 4, 6 and 8 weeks of therapy.

Results: Compared to the placebo group, the duloxetine group showed significantly higher improvement in negative symptoms (p<0.001), PANSS total (p<0.001), and the general psychopathology subscale scores (p=0.001), but no significant difference in positive symptoms (p=0.13). The side effect profiles of the 2 treatment regimens were not significantly different.

Discussion: Duloxetine adjuvant to risperidone seems to be a tolerable and efficacious treatment for primary negative symptoms of schizophrenia.

* The first three authors contributed equally to this work