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.
Key words duloxetine - SNRI - schizophrenia - clinical trial