Mirtazapine in schizophrenia - an undeservedly overlooked option?

Mirtazapine has often been prescribed as add-on treatment for schizophrenia in patients with suboptimal response to conventional treatments. In this review, we evaluate the existing evidence for efficacy and effectiveness of add-on mirtazapine in schizophrenia and reappraise the practical and theoretical aspects of mirtazapine-antipsychotic combinations. In randomized controlled trials (RCTs), mirtazapine demonstrated favourable effects on negative and cognitive (although plausibly not depressive) symptoms, with no risk of psychotic exacerbation. Mirtazapine also may have a desirable effect on antipsychotic-induced sexual dysfunction, but seems not to alleviate extrapyramidal symptoms, at least if combined with second-generation antipsychotics. It is noteworthy that all published RCTs have been underpowered and relatively short in duration. In the only large pragmatic effectiveness study that provided analyses by add-on antidepressant, only mirtazapine was associated with both decreased rate of hospital admissions and number of in-patient days. Mirtazapine hardly affects the pharmacokinetics of antipsychotics. However, possible pharmacodynamic interactions (sedation and metabolic offence) should be borne in mind. The observed desired clinical effects of mirtazapine may be due to its specific receptor-blocking properties. Alternative theoretical explanations include its possible neuroprotective effect. Further well-designed RCTs and real-world effectiveness studies are needed to determine whether add-on mirtazapine should be recommended for difficult-to-treat schizophrenia.

Should patients with schizophrenia receive antidepressants?

Antipsychotics play a key role in the pharmacological treatment of schizophrenia, and monotherapy is effective for most patients. Achieving an optimal treatment response is, however, often difficult. Combining an antidepressant drug to the antipsychotic regimen could potentially improve treatment outcomes, although the evidence supporting the use of such combinations is limited and contradictory. Positive evidence has mostly been obtained from the efficacy of antidepressants acting on monoamine receptors on the negative symptoms of schizophrenia. These receptor-active drugs may also improve cognition in schizophrenic patients. In the light of current knowledge, antidepressants do not appear to potentiate the psychotic symptoms of schizophrenic patients. However, there is no robust evidence of the efficacy of antidepressants in the treatment of schizophrenia-related depression, and thus monotherapy with an antipsychotic drug is recommended for treating it. If using antidepressants in addition to antipsychotics is deemed necessary, the risk of pharmacodynamic and pharmacokinetic interactions should be kept in mind.

Add-on mirtazapine improves orgasmic functioning in patients with schizophrenia treated with first-generation antipsychotics.

AIM: Sexual dysfunction, common in schizophrenia, may be further exaggerated by antipsychotics, especially those of First Generation (FGAs), and antidepressants, such as Selective Serotonin Reuptake Inhibitors (SSRs). Mirtazapine, an antidepressant characterized by its different action mechanism compared with that of the majority of other antidepressants, may improve SSRI-induced sexual dysfunction in patients with depression. It is unknown, however, whether mirtazapine improves sexual functioning in schizophrenia. METHODS: This study randomly assigned FGA-treated patients with schizophrenia to receive either an add-on mirtazapine (n = 20) or a placebo (n = 19) for 6 weeks. Sexual functioning was prospectively measured using five relevant items from the Udvalg for Kliniske Undersogelser side-effect rating scale (UKU-SERS). RESULTS: Orgasmic function improved with statistical significance in the mirtazapine group (p = .03), with no changes in any other sexual functions in either group. CONCLUSION: Add-on mirtazapine appears to relieve orgasmic dysfunction in FGA-treated patients with schizophrenia.

Is there an interrelationship between the effects of antipsychotics on psychopathology and on metabolism?

BACKGROUND: Increased body weight and hyperlipidemia caused by antipsychotics may be associated with improved antipsychotic efficacy in schizophrenia. If this association has a causal interrelationship via a genuine pathophysiological mechanism, then body weight loss in antipsychotic-treated patients would be accompanied by worsened psychopathology. This could have clinical implications. AIM: To explore whether the decreased body weight in these patients is associated with a worsened psychopathology. METHODS: In our previously published study, a 16 week treatment period with add-on orlistat (but not placebo) resulted in body weight loss in male (but not female) clozapine- or olanzapine-treated overweight or obese patients. In the current study, we investigated whether body weight loss in those male patients could worsen psychosis. Changes in the Positive and Negative Syndrome Scale (PANSS) scores within groups and body weight changes and lipid profiles over the treatment period were analysed by the paired samples t-test. Between-group comparisons were analysed by the independent samples t-test. RESULTS: Over the treatment period body weight decreased by 2.56 ± 3.25 kg from initial 106.02 ± 12.61 kg (p = 0.04) for the orlistat group, with no statistically significant changes for the placebo group. Lipid levels did not change in either group. The orlistat-induced weight decrease was not associated with worsening in the PANSS scores. CONCLUSIONS: Weight loss was not associated with a worsening of psychosis. The interrelationship between the antipsychotic-induced weigh gain and improved schizophrenia psychopathology observed in earlier studies appears to be indirect. Orlistat treatment in our study did not worsen psychopathology in this population.

Randomized Controlled Trials of Add-On Antidepressants in Schizophrenia.

BACKGROUND: Despite adequate treatment with antipsychotics, a substantial number of patients with schizophrenia demonstrate only suboptimal clinical outcome. To overcome this challenge, various psychopharmacological combination strategies have been used, including antidepressants added to antipsychotics. METHODS: To analyze the efficacy of add-on antidepressants for the treatment of negative, positive, cognitive, depressive, and antipsychotic-induced extrapyramidal symptoms in schizophrenia, published randomized controlled trials assessing the efficacy of adjunctive antidepressants in schizophrenia were reviewed using the following parameters: baseline clinical characteristics and number of patients, their on-going antipsychotic treatment, dosage of the add-on antidepressants, duration of the trial, efficacy measures, and outcomes. RESULTS: There were 36 randomized controlled trials reported in 41 journal publications (n=1582). The antidepressants used were the selective serotonin reuptake inhibitors, duloxetine, imipramine, mianserin, mirtazapine, nefazodone, reboxetin, trazodone, and bupropion. Mirtazapine and mianserin showed somewhat consistent efficacy for negative symptoms and both seemed to enhance neurocognition. Trazodone and nefazodone appeared to improve the antipsychotics-induced extrapyramidal symptoms. Imipramine and duloxetine tended to improve depressive symptoms. No clear evidence supporting selective serotonin reuptake inhibitors' efficacy on any clinical domain of schizophrenia was found. Add-on antidepressants did not worsen psychosis. CONCLUSIONS: Despite a substantial number of randomized controlled trials, the overall efficacy of add-on antidepressants in schizophrenia remains uncertain mainly due to methodological issues. Some differences in efficacy on several schizophrenia domains seem, however, to exist and to vary by the antidepressant subgroups--plausibly due to differences in the mechanisms of action. Antidepressants may not worsen the course of psychosis. Better designed, larger, and longer randomized controlled trials are needed.

Development of self-image and its components during a one-year follow-up in non-referred adolescents with excess and normal weight.

BACKGROUND: The proportion of overweight and obese youths is high. The present study aimed to investigate the development of self-image and its components during a one-year follow-up among non-referred adolescents with excess and normal weight. Furthermore, we separately analyzed the data for girls and boys. METHODS: Altogether 86 8(th) grades (41 girls and 45 boys) with a relative weight of 26% or more above the median and 91 controls (43 girls and 48 boys) with normal weight participated the follow-up. The Offer Self-Image Questionnaire, Revised (OSIQ-R) was used to assess self-image at baseline and on follow-up. In the OSIQ-R, a low total raw score implies positive adjustment, while a high raw score implies poor adjustment and a negative self-image. The study design was doubly correlated (pairs and time), and a linear mixed model was used in the statistical analysis. RESULTS: In OSIQ-R total scores, a comparative improvement was observed in girls with normal weight. Among these girls, significant change scores compared to zero were seen in impulse control, social functioning, vocational attitudes, self-confidence, self-reliance, body image, sexuality, and ethical values. In girls with excess weight, none of the change scores compared to zero were statistically significant. When the girls with normal and excess weight were compared, the difference in change scores was largest in sexuality and vocational attitudes. Change scores compared to zero were significant in sexuality and idealism for boys with excess weight, and in impulse control, mental health, self-reliance, and sexuality for normal weight boys. When the boys with excess and normal weight were compared, no statistically significant differences emerged in change scores. CONCLUSION: In mid-adolescent girls, the influence of overweight and obesity on the development of self-image is substantial. Weight management programs directed at overweight adolescent girls should include psychological interventions aiming to diminish self-image distress, especially that associated with feelings, attitudes, and behavior towards the opposite sex, as well as future career plans.

Predictors and mediators of add-on mirtazapine-induced cognitive enhancement in schizophrenia--a path model investigation.

We aimed to evaluate predictors and mediators of enhancing effect of adjunctive mirtazapine on cognition in schizophrenia. Patients with difficult-to-treat schizophrenia received either mirtazapine (n = 19) or placebo (n = 18) in a double-blind fashion for six weeks. Mirtazapine outperformed placebo on the Block Design and Stroop Dots. In the present subsidiary study, factors underlying this difference were explored with Path Analysis. Add-on mirtazapine had an independent enhancing effect on the Block Design-measured visuo-spatial functioning. Further, this effect was mediated via changes in positive, depressive and parkinsonism symptoms, but not in negative symptoms. This effect was predicted by higher doses of FGAs, longer duration of illness and lower initial Block Design scores. Path Analysis model fit was good. Mirtazapine may have direct and indirect favorable effects on visuo-spatial functioning, but further research is needed. Path analysis may be a feasible statistical method for further research of neurocognition in psychopharmacological interventions in schizophrenia. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

Relationships between pharmacotherapy-induced metabolic changes and improved psychopathology in schizophrenia: data from a mirtazapine and first-generation antipsychotics combination trial.

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.

In a randomized placebo-controlled add-on study orlistat significantly reduced clozapine-induced constipation.

Constipation is a common and potentially fatal side effect of clozapine treatment. Another important side effect of clozapine may also be significant weight gain. Orlistat is a weight-control medication that is known to induce loose stools as a common side effect. This study aimed to explore whether orlistat used to control clozapine-induced weight gain can simultaneously tackle clozapine-related constipation. In this 16-week randomized-controlled study, clozapine-treated patients received add-on orlistat (n=30) or add-on placebo (n=24). Colonic function was measured using the Bristol Stool Form Scale. There was a significant (P=0.039) difference in the prevalence of constipation in favor of orlistat over placebo in completers (n=40) at the endpoint. A decrease in the prevalence of constipation within the orlistat group (P=0.035) was observed (vs. no statistically significant changes in the placebo group). In clozapine-treated patients, orlistat may be beneficial not only for weight control but also as a laxative. As no established treatments for clozapine-induced constipation exist, orlistat can be considered for this population, although more studies are required.

Add-on mirtazapine improves depressive symptoms in schizophrenia: a double-blind randomized placebo-controlled study with an open-label extension phase.

Depression is common in schizophrenia and worsens its course. The role of antidepressants for schizophrenic depression remains unclear. In this study, the efficacy of add-on mirtazapine on depression in schizophrenia was explored in a subsidiary arm of a recent randomized controlled trial. Patients (n = 41) with chronic but stable schizophrenia and inadequate response to stable doses of different first-generation antipsychotics were treated with add-on mirtazapine 30 mg or placebo during a 6-week double-blind phase and with open-label add-on mirtazapine during a 6-week extension phase. Efficacy measures were the Calgary Depression Scale for Schizophrenia (CDSS) and the Positive and Negative Syndrome Scale depression item. During the double-blind phase, both measures' scores decreased significantly in the mirtazapine group but not in the placebo group (for the CDSS, 52.0% vs 19.6%, respectively). During the open­label phase, both groups demonstrated significant improvements. In between­group comparison, a trend favoring mirtazapine did not reach statistical significance. The changes in the CDSS correlated positively with those in the Positive and Negative Syndrome Scale negative, positive and total (sub)scales for mirtazapine­treated patients during the double­blind phase. Depressed patients with schizophrenia may benefit from mirtazapine­first­generation antipsychotics combination, with no increased risk for psychosis. However, more studies are needed.

Orlistat in clozapine- or olanzapine-treated patients with overweight or obesity: a 16-week open-label extension phase and both phases of a randomized controlled trial.

OBJECTIVE: To explore long-term effects of orlistat in adult clozapine- or olanzapine-treated patients with DSM-IV-diagnosed schizophrenia and overweight or obesity who tolerate orlistat. METHOD: Orlistat or placebo was added to clozapine or olanzapine in stable doses in a 16-week randomized controlled trial. Open-label orlistat was added to the antipsychotics during a 16-week extension phase for those completing the double-blind phase. No low-calorie diet or participation in behavioral programs was required. Body weight (primary outcome) and some metabolic parameters were measured prospectively. Analyses were performed for those completing both phases (ie, population differing from that reported earlier). The study was conducted from 2004 through 2005. RESULTS: During the open-label phase, the 44 patients experienced mean ± SD body weight loss of -1.29 ± 3.04 kg, P = .007. During both phases, men (but not women) showed a weight loss of -2.39 ± 5.45 kg, P = .023. Some subgroups showed desirable changes in several metabolic parameters. Prolonged (32 weeks) orlistat treatment yielded no additional benefits as compared to short (16 weeks) treatment. CONCLUSIONS: In clozapine- or olanzapine-treated overweight or obese patients able to take orlistat on a long-term basis, the drug, with no concomitant hypocaloric diet or behavioral interventions, caused moderate weight loss only in men. However, some metabolic benefits may be achieved independently of weight changes. In patients who do not respond to orlistat within the first 16 weeks, continuation treatment may provide no additional benefits. TRIAL REGISTRATION: controlled-trials.com Identifier: ISRCTN65731856.

More evidence on additive antipsychotic effect of adjunctive mirtazapine in schizophrenia: an extension phase of a randomized controlled trial.

OBJECTIVE: Adjunctive mirtazapine improved negative symptoms of schizophrenia in several studies. Recently, we found an improvement also in positive symptoms when mirtazapine was added to first generation antipsychotics (FGAs) in a 6 week randomized controlled trial (RCT). The short duration of that trial was its limitation. This study aimed to explore whether longer treatment is worthwhile. METHOD: Completers of the RCT (n = 39) received open-label add-on mirtazapine for additional 6 weeks. The Positive and Negative Syndrome Scale (PANSS) total score (primary outcome) and several other clinical parameters were measured prospectively. RESULTS: During the open-label phase, significant improvement was achieved in all parameters, with an effect size of 0.94 (CI 95% = 0.45-1.43) on the primary outcome and an impressive additive antipsychotic effect. Patients who received mirtazapine during both phases demonstrated greater improvement in positive symptoms (29.6% versus 21.2%, p = 0.027) than those who received mirtazapine during open-label extension phase only. CONCLUSIONS: These findings support our previous data on the additive antipsychotic effect of mirtazapine in FGAs-treated schizophrenia. Mirtazapine may be effective in other symptom domains, too. Longer duration of mirtazapine treatment may yield additional benefits. If these results will be confirmed in larger studies, add-on mirtazapine may become a feasible option in difficult-to-treat schizophrenia.