Negative symptoms of schizophrenia are characterized by affective flattening, alogia, avolition, and anhedonia and are often nonresponsive to antipsychotic therapy. Because negative symptoms are predictive of poor occupational and social functioning, as well as poor global outcomes, numerous studies evaluating adjunct therapy to antipsychotics have been conducted. This review focuses on the use of the antidepressant mirtazapine as adjunct therapy to antipsychotics for the treatment of negative symptoms of schizophrenia. A literature search of the MEDLINE database (from inception-March 2011) identified eight relevant articles: six were randomized, double-blind, placebo-controlled trials, and two were open-label trials. Of the six randomized trials reviewed, four studies assessed add-on mirtazapine to second-generation antipsychotics, whereas two studies examined add-on mirtazapine to first-generation antipsychotics. Five of the six randomized trials supported the use of mirtazapine for negative symptoms of schizophrenia. Of the two open-label trials, one naturalistic study demonstrated that mirtazapine add-on therapy to clozapine was not associated with improvements in negative symptoms; however, this study focused primarily on improvements in cognition, not negative symptoms. An open-label extension phase to a randomized controlled trial showed that mirtazapine continued to produce significant improvement in negative symptoms over a longer duration of time, when added to first-generation antipsychotic therapy. Overall, mirtazapine appears to be well tolerated and associated with few drug interactions. Although adjunct mirtazapine to antipsychotics has been shown to be effective at doses of 30 mg/day in most of the trials, limitations of these studies include short study duration and small sample sizes. To improve generalizability, larger multicenter studies with broader inclusion criteria should be conducted. In addition, studies of longer duration that use different mirtazapine dosages are needed to further assess the benefits of mirtazapine for negative symptoms of schizophrenia.
[Show abstract][Hide abstract] ABSTRACT: Recent research suggests that inflammation and immunity may have a role in the etiology of psychotic disorders. There is evidence of proinflammatory activation of the innate immune system and an activation of the T-cells of the adaptive immune system in both schizophrenia and bipolar disorder. Studies of antipsychotic-naïve patients with first-episode psychosis have found that inflammation is present already at this stage. Some of these abnormalities resolve after the initiation of treatment, suggesting that they are state markers of acute psychosis, but other abnormalities persist. There is also evidence for prenatal infections being involved in the etiology of schizophrenia. Several hypotheses link inflammation and immunity with psychotic disorders. In this review, we focus on hypotheses related to prenatal development, disturbed regulation of neurogenesis, microglial activation, autoimmunity and microbial environment, and consider the potential confounding effects related to stress, childhood adversities, lifestyle and medical comorbidity as well as some methodological limitations. We also review the current evidence for the effectiveness of anti-inflammatory medication in the treatment of psychotic disorders.
[Show abstract][Hide abstract] ABSTRACT: Clinical efficacy and metabolic side-effects of antipsychotics seem to correlate with each other. In this study, interrelationship of similar metabolic effects of mirtazapine and its earlier reported desirable effects on psychopathology in first-generation antipsychotics (FGAs)-treated schizophrenia were explored. Symptomatic FGAs-treated patients with schizophrenia received a 6-wk double-blind treatment with add-on mirtazapine (n = 20) or placebo (n = 16), followed by a 6-wk open-label mirtazapine treatment. Mirtazapine (but not placebo) induced an increase in body weight and cholesterol levels. The latter was associated with a clinical improvement in all (sub)scales of the Positive and Negative Syndrome Scale [PANSS; an increase of cholesterol by 1 mmol/l predicted 7 points reduction on the PANSS total score (r = 0.85, p = 0.001)]. In schizophrenia, mirtazapine-induced weight gain and increase of total cholesterol are associated with the improved efficacy of mirtazapine-FGAs combination - a novel observation with possible clinical and theoretical implications.
The International Journal of Neuropsychopharmacology 12/2012; 16(07):1-6. DOI:10.1017/S146114571200137X · 4.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Context: Despite advances made in treating the positive symptoms of schizophrenia, treatment of negative symptoms remains an unmet therapeutic need. Adjunctive mirtazapine has shown promise for treatment of negative symptoms in several small clinical trials.Objective: To assess the efficacy of mirtazapine as an adjunctive treatment of negative symptoms in patients with chronic schizophrenia via meta-analysis.Data Sources: A systematic literature review of articles in English and Spanish was conducted in November 2011 by searching PubMed, the Cochrane Library, the Clinical Trial Registry of the NIH, and SIGLE (System for Grey Literature in Europe). Free text search terms for PubMed were 'schizophrenia,' 'negative symptoms' and 'mirtazapine.' Publication date was not a limitation.Study Selection: Studies of people with schizophrenia/schizoaffective disorder were included in the meta-analysis if they were randomized, double-blind, and used the Positive and Negative Symptom Scale (PANSS) as an outcome measure. Nine studies were initially identified. Five studies were included in the meta-analysis; 1 study was excluded for not using the PANSS, 3 were excluded as representing duplicate publications and open label phases of one of the selected randomized control trials. Studies varied in the quality of their selection for participants with primary negative symptoms.Results: Three of the 5 studies showed significant improvement in negative symptoms individually. The overall analysis showed improvement in negative symptoms with an effect size of 1.00 (0.084-1.918), which was statistically significant (p=0.032). Data from the negative symptoms subscale of the PANSS from 169 subjects was used in a forest plot to illustrate the relative strength of treatment effects. The variation in standard median deviation (SMD) attributable to heterogeneity was 27.35 %, indicating a high degree of heterogeneity.Conclusions: This meta-analysis supports the hypothesis that adding mirtazapine to treatment with antipsychotics can improve negative symptoms in schizophrenia. However, additional studies with more stringent negative symptom selection criteria and homogeneous use of antipsychotics are needed.
Clinical Schizophrenia & Related Psychoses 03/2013; 1(-1):1-24. DOI:10.3371/CSRP.VIRE.030813
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