Change of prescription for patients with schizophrenia or major depressive disorder during admission: real-world prescribing surveys from the effectiveness of guidelines for dissemination and education psychiatric treatment project.

BACKGROUND: Polypharmacy of additional psychotropics alongside the main treatment drug (antipsychotics in schizophrenia and antidepressants in major depressive disorder) is common in Japan. Our goal is to align psychotropic prescription in Japan with international standards, while reducing the differences between facilities. To achieve this goal, we aimed to compare prescriptions at the time of hospital admission and discharge. METHODS: Data on prescriptions at admission and discharge from 2016 to 2020 were collected. We divided the patients into four groups: (1) mono_mono group, monotherapy of the main drug at admission and discharge; (2) mono_poly group, monotherapy at admission and polypharmacy at discharge; (3) poly_poly group, polypharmacy at admission and discharge; and (4) poly_mono group, polypharmacy at admission and monotherapy at discharge. We compared the changes in dosage and number of psychotropics among the four groups. RESULTS: For both schizophrenia and major depressive disorder, the patients who received monotherapy with the main drug at admission were likely to receive main drug monotherapy at discharge and vice versa. For schizophrenia, the polypharmacy was prescribed more often in the mono_poly group than that in the mono_mono group. The prescription was not changed at all for more than 10% of the patients. CONCLUSIONS: It is critical to avoid a polypharmacy regimen to ensure that guideline-compliant treatment is provided. We expect higher rates of monotherapy with the main drug after the EGUIDE lectures. TRIAL REGISTRATION: The study protocol was registered in the University Hospital Medical Information Network Registry (UMIN000022645).

Combination Psychotropic Use for Schizophrenia With Long-Acting Injectable Antipsychotics and Oral Antipsychotics: A Nationwide Real-World Study in Japan.

BACKGROUND: Although several guidelines recommend monotherapy with antipsychotics for the treatment of schizophrenia, patients who receive long-acting injectable antipsychotics (LAIs) are frequently treated with oral antipsychotics (OAPs). In the present study, we investigated the detailed use of psychotropic medications among patients throughout Japan with schizophrenia who received LAIs or OAPs. METHODS: The present study used data from the project for the Effectiveness of Guidelines for Dissemination and Education in psychiatric treatment from 94 facilities in Japan. The LAI group included patients who received any LAI, and the non-LAI group included patients who took only OAP medications at discharge. The participants of this study were 2518 schizophrenia patients (263 in the LAI group and 2255 in the non-LAI group) who received inpatient treatment and had prescription information at discharge between 2016 and 2020. RESULTS: This study revealed significantly higher rates of polypharmacy antipsychotics, number of antipsychotics, and chlorpromazine equivalents in the LAI group than in the non-LAI group. In contrast, the LAI group showed lower rate of concomitant use of hypnotic and/or antianxiety medication than the non-LAI group. CONCLUSIONS: Presenting these real-world clinical results, we want to encourage clinicians to keep monotherapy in mind for the treatment of schizophrenia, especially by reducing concomitant use of antipsychotics in the LAI group and reducing hypnotic and/or antianxiety medication in the non-LAI group.

Prescription of Anticholinergic Drugs in Patients With Schizophrenia: Analysis of Antipsychotic Prescription Patterns and Hospital Characteristics.

In several clinical guidelines for schizophrenia, long-term use of anticholinergic drugs is not recommended. We investigated the characteristics of the use of anticholinergics in patients with schizophrenia by considering psychotropic prescription patterns and differences among hospitals. A cross-sectional, retrospective prescription survey at the time of discharge was conducted on 2027 patients with schizophrenia from 69 Japanese hospitals. We examined the relations among psychotropic drug prescriptions regarding anticholinergic prescription. We divided the hospitals into three groups-low rate group (LG), medium rate group (MG), and high rate group (HG)-according to their anticholinergic prescription rates, and analyzed the relationship between anticholinergic prescription rates and antipsychotic prescription. Anticholinergic drugs were prescribed to 618 patients (30.5%), and the prescription rates were significantly higher for high antipsychotic doses, antipsychotic polypharmacy, and first-generation antipsychotics (FGAs) use. The anticholinergic prescription rate varied considerably among hospitals, ranging from 0 to 66.7%, and it was significantly higher in patients with antipsychotic monotherapy, antipsychotic polypharmacy, and normal and high doses of antipsychotics in HG than in those LG and MG. The anticholinergics prescription rate in patients with second-generation antipsychotic monotherapy in HG was also significantly higher than in those LG and MG; however, the difference was no longer significant in patients with FGA monotherapy. Conclusively, in addition to high antipsychotic doses, antipsychotic polypharmacy, and FGA use, hospital characteristics influence the prescribing of anticholinergic drugs.

Clozapine Treatment Is Associated With Higher Prescription Rate of Antipsychotic Monotherapy and Lower Prescription Rate of Other Concomitant Psychotropics: A Real-World Nationwide Study.

BACKGROUND: Although clozapine is effective for treatment-resistant schizophrenia (TRS), the rate of clozapine prescription is still low. Whereas antipsychotic monotherapy is recommended in clinical practice guidelines, the rate of antipsychotic polypharmacy is still high. There is little evidence on whether a clozapine prescription influences changes in the rate of monotherapy and polypharmacy, including antipsychotics and other psychotropics. We therefore hypothesized that the rate of antipsychotic monotherapy in patients with TRS who were prescribed clozapine would be higher than that in patients with schizophrenia who were not prescribed clozapine. METHODS: We assessed 8306 patients with schizophrenia nationwide from 178 institutions in Japan from 2016 to 2019. We analyzed the psychotropic prescription data at discharge in patients diagnosed with TRS and with no description of TRS (ND-TRS) based on the diagnosis listed in the discharge summary. RESULTS: The rate of antipsychotic monotherapy in the TRS with clozapine group (91.3%) was significantly higher than that in the TRS without clozapine group (45.9%; P < 2.0 × 10-16) and the ND-TRS without clozapine group (54.7%; P < 2.0 × 10-16). The rate of antipsychotic monotherapy without any other concomitant psychotropics in the TRS with clozapine group (26.5%) was significantly higher than that in the TRS without clozapine group (12.6%; P = 1.1 × 10-6) and the ND-TRS without clozapine group (17.0%; P = 5.9 × 10-6). CONCLUSIONS: Clozapine prescription could be associated with a high rate of antipsychotic monotherapy. Patients will benefit from the correct diagnosis of TRS and thus from proper clozapine prescription.

Pre-treatment plasma cytokine levels as potential predictors of short-term remission of depression.

OBJECTIVES: The response to antidepressants varies significantly among individuals and is difficult to predict before treatment. In this randomised control trial, we explored cytokines that correlate with the therapeutic effect of mirtazapine (MIR) and selective serotonin reuptake inhibitors (SSRIs) and whether they could be predictors of remission for each antidepressant. METHODS: Plasma cytokines, such as tumour necrosis factor-α (TNF-α), interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) were assayed in 95 participants before medication and assayed by the enzyme-linked immunosorbent assay. The Hamilton Rating Scale for Depression assessed depressive symptoms over 4 weeks. RESULTS: In the SSRI group, the baseline GM-CSF level was significantly higher in the remission group than in the non-remission group (p = .022). In the MIR group, the baseline level of TNF-α was significantly higher (p = .039) and IL-2 was lower (p = .032) in the remission group than in the non-remission group. In patients prescribed with MIR, the cut-off values of TNF-α (10.035 pg/mL) and IL-2 (1.170 pg/mL) calculated from the receiver operating characteristic curve suggested that the remission rate, which corresponds to a positive predictive value, could be increased from 31.3% to 60.0% and 50.0%, respectively. For those prescribed with SSRIs, the remission rate was 37.0% and using the cut-off value of GM-CSF (0.205 pg/mL), the remission rate could be almost doubled to 70%. CONCLUSIONS: Our study shows that pre-treatment plasma concentrations of TNF-α, IL-2, and GM-CSF may suggest the predictability of remission by SSRIs or MIR.

The characteristics of patients receiving psychotropic pro re nata medication at discharge for the treatment of schizophrenia and major depressive disorder: A nationwide survey from the EGUIDE project.

BACKGROUND: Although several guidelines indicate that daily pharmacotherapy is an important part of the treatment of schizophrenia and major depressive disorder, there are few reports regarding pro re nata (PRN) prescriptions. The purpose of this study is to clarify the characteristics of patients receiving psychotropic PRN prescription for the treatment of schizophrenia and major depressive disorder. METHOD: We used data from 'the effectiveness of guideline for dissemination and education in psychiatric treatment' (EGUIDE) project to evaluate the presence or absence of psychotropic PRN prescription at the time of discharge, the age and sex of patients receiving PRN prescription for each diagnosis, and the association between PRN prescription and regular daily psychotropics. RESULTS: The psychotropic PRN prescription ratio was 29.9% among 2617 patients with schizophrenia and 31.1% among 1248 patients with major depressive disorder at discharge. In schizophrenia, the psychotropic PRN prescription ratio was 21.6% for patients aged 65 years or older, which was lower than that of all other age groups. In major depressive disorder, the psychotropic PRN prescription ratio was 34.2% for female patients, which was significantly higher than that for male patients (25.5%). In schizophrenia, there was an association between psychotropic PRN prescription and regular use of multiple psychotropic medications. CONCLUSIONS: Psychotropic PRN prescription was less common in elderly patients with schizophrenia and more common in female patients with major depressive disorder. In schizophrenia, psychotropic PRN prescription led to polypharmacy of psychotropics. Further studies are needed to accumulate evidence and to provide education on appropriate PRN prescriptions.

Characteristics of discharge prescriptions for patients with schizophrenia or major depressive disorder: Real-world evidence from the Effectiveness of Guidelines for Dissemination and Education (EGUIDE) psychiatric treatment project.

BACKGROUND: Monopharmacy with antipsychotics and antidepressants is the first-line treatment for schizophrenia and major depressive disorder (MDD) in most clinical guidelines, while polypharmacy with psychotropic agents in the treatment of schizophrenia is common in clinical practice. There are no detailed data on the prescription patterns for inpatients with mental illness with reliable diagnoses made by treating psychiatrists. METHODS: We gathered prescription data at discharge from 2177 patients with schizophrenia and 1238 patients with MDD from October 2016 to March 2018. RESULTS: The patients with schizophrenia aged between 60 and 79 were prescribed lower doses of antipsychotics and hypnotics/anxiolytics than those aged between 40 and 59. There were significant differences between the prescription rate of antipsychotics in the patients with schizophrenia and that of antidepressants in the patients with MDD. The frequency of concomitant drugs such as anti-Parkinson drugs, anxiolytics/hypnotics and mood stabilizers in the subjects with schizophrenia prescribed antipsychotic polypharmacy was significantly higher than that with monotherapy. For the patients with schizophrenia, olanzapine, risperidone, aripiprazole, quetiapine, and blonanserin were the five most prescribed antipsychotics. For the patients with MDD, mirtazapine, duloxetine, escitalopram, trazodone and sertraline were the five most prescribed antidepressants. CONCLUSIONS: Our results showed the use of high doses of antipsychotics, high percentages of antipsychotic polypharmacy and concurrent use of hypnotics/anxiolytics in patients with schizophrenia. Notably, these data were collected before intensive instruction regarding the guidelines; therefore, we need to assess the change in the prescription pattern post guideline instruction.

Prescription patterns in patients with schizophrenia in Japan: First-quality indicator data from the survey of "Effectiveness of Guidelines for Dissemination and Education in psychiatric treatment (EGUIDE)" project.

BACKGROUND: Guideline for Pharmacological Therapy for Schizophrenia was published by the Japanese Society of Neuropsychopharmacology in 2015. "Effectiveness of Guidelines for Dissemination and Education in psychiatric treatment (EGUIDE)" project aimed to standardize medical practice using quality indicators (QIs) as indices to evaluate the quality of medical practice. In this study, we have reported the quality indicator values of prescription before the beginning of the guideline lectures in the EGUIDE project to ascertain the baseline status of treating patients with schizophrenia. METHODS: A cross-sectional, retrospective case record survey was conducted, involving 1164 patients with schizophrenia at the time of discharge. We checked all types and dosage of psychotropic drugs. RESULTS: Forty-three percent of patients had antipsychotic polypharmacy, and substantial concomitant medication was observed (antidepressants; 8%, mood stabilizers: 37%, anxiolytics or hypnotics: 68%). CONCLUSIONS: In the results obtained in this study, we plant to report changes in the effectiveness of education in the EGUIDE project near the future.

Relationships between serum brain-derived neurotrophic factor, plasma catecholamine metabolites, cytokines, cognitive function and clinical symptoms in Japanese patients with chronic schizophrenia treated with atypical antipsychotic monotherapy.

OBJECTIVES: Catecholamines, brain-derived neurotrophic factor (BDNF) and cytokines may be involved in the pathophysiology of schizophrenia. The aim of this study was to examine the associations between serum BDNF levels, plasma catecholamine metablolites, cytokines and the cognitive functions of patients with schizophrenia treated with atypical antipsychotic monotherapy. METHODS: One hundred and forty-six patients with schizophrenia and 51 age- and sex-matched healthy controls were examined for peripheral biological markers and neurocognitive test. RESULTS: There were positive correlations between serum BDNF levels and scores for verbal memory and attention and processing speed as well as between serum BDNF levels and negative symptoms. Furthermore, there was a negative correlation between the plasma homovanillic acid (HVA) level and motor function and a positive correlation between the plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) level and attention and processing speed. There were no significant correlations between interleukin-6 or tumour necrosis factor alpha and cognitive function. Moreover, there were no significant correlations between the plasma levels of HVA, MHPG, cytokines and clinical symptoms. CONCLUSIONS: Serum BDNF levels are positively related to the impairment of verbal memory and attention, plasma HVA levels are positively related to motor function, and plasma MHPG levels are positively related to attention in patients with schizophrenia.

Abnormal white matter integrity in the corpus callosum among smokers: tract-based spatial statistics.

In the present study, we aimed to investigate the difference in white matter between smokers and nonsmokers. In addition, we examined relationships between white matter integrity and nicotine dependence parameters in smoking subjects. Nineteen male smokers were enrolled in this study. Eighteen age-matched non-smokers with no current or past psychiatric history were included as controls. Diffusion tensor imaging scans were performed, and the analysis was conducted using a tract-based special statistics approach. Compared with nonsmokers, smokers exhibited a significant decrease in fractional anisotropy (FA) throughout the whole corpus callosum. There were no significant differences in radial diffusivity or axial diffusivity between the two groups. There was a significant negative correlation between FA in the whole corpus callosum and the amount of tobacco use (cigarettes/day; R = - 0.580, p = 0.023). These results suggest that the corpus callosum may be one of the key areas influenced by chronic smoking.

Switching to antipsychotic monotherapy can improve attention and processing speed, and social activity in chronic schizophrenia patients.

OBJECTIVE: This study sought to examine whether switching polypharmacy therapy to monotherapy would improve the cognitive function and social function of patients with schizophrenia. METHODS: Thirty-nine patients with schizophrenia who were receiving therapy with two antipsychotics were randomly divided into a switch to monotherapy group (switching group) and a polypharmacy continued group (continuing group). For the patients allocated to the switching group, the dose level of one of the two antipsychotic drugs was gradually reduced to zero. Psychotic symptoms, cognitive function and social function scale scores were assessed immediately before and 24 weeks after switching, and the time courses of these scores were compared between the two groups. RESULTS: Compared with the continuing group, the switching group demonstrated significantly greater improvement in attention after switching (p = 0.02). Furthermore, the improvement in daily living (p = 0.038) and work skills (p = 0.04) was significantly greater in the switching group. In an analysis of the correlation among sub-items with respect to the degrees of improvement, a significant correlation was noted between improvement in executive function and improvement in daily living (r = -0.64, p = 0.005) and between improvement in work skills and improvement in attention (r = -0.51, p = 0.038). CONCLUSION: In patients with schizophrenia receiving polypharmacy, switching to monotherapy resulted in improvements in attention. Furthermore, improvements in executive function led to improvements in daily living, and improvements in attention led to improvements in work skills. Thus, switching to monotherapy is a useful option.

Plasma levels of interleukin-6 and selective serotonin reuptake inhibitor response in patients with major depressive disorder.

OBJECTIVE: We investigated the plasma levels of interleukin (IL)-6 and 5-HTT polymorphisms in patients with major depressive disorder (MDD). This is the first report, to our knowledge, of an investigation into the association between 5-HTT gene polymorphism, plasma IL-6 levels, and responses to selective serotonin reuptake inhibitors (SSRIs) in Japanese patients with MDD. METHOD: One-hundred and eighteen patients (51 male, 67 female) who met the DSM-IV criteria for MDD were enrolled. Their ages ranged from 24 to 78 (mean ± SD = 44 ± 12) years. The patients were treated with SSRIs (paroxetine in 66 cases, sertraline in 42 cases) for 8 weeks. RESULTS: The plasma levels of IL-6 were significantly higher in the SSRI responders than in the nonresponders (p = 0.0328), and the changes in plasma IL-6 levels correlated significantly with the changes in severity of depressive state (p = .0.007). No difference was found in baseline and the changes in plasma IL-6 levels between the patients with a 5-HTT gene (5-HTTLPR) L-carrier and those with S/S. CONCLUSION: These results suggest that the plasma levels of IL-6 reflect the severity of MDD and that plasma IL-6 levels might be another biological-state marker for the depressive state. In addition, the 5-HTTLPR polymorphism might be independent of plasma IL-6 levels.

Current smoking rate in patients with psychiatric disorders in Japan: questionnaire survey.

The association between smoking and psychiatric disorders (PD) has been known for many years. Support for smoking cessation among patients with PD is provided in advanced nations, but there is a little support for smoking cessation among patients with PD in Japan, where few studies have investigated the smoking rate. The aim of the present study is to determine the smoking rate and smoking habits of Japanese patients with PD. The subjects included outpatients who visited the outpatient psychiatric clinic at a University hospital between January and March of 2011. They answered a questionnaire consisting of questions about their sociodemographic background and smoking habits. In an analysis of 733 subjects, the overall smoking rate was 25.1%. The smoking rates among the patients with schizophrenia and depression were 17.3% and 23.9%, respectively, and these rates were lower than the results of previous studies. Among the current smokers, 43.4% had experienced smoking cessation, and only 26.1% were not interested in smoking cessation. Of the current smokers, 37.5% spent between US$128.88 and US$257 per month on cigarettes.

Several prescription patterns of antipsychotic drugs influence cognitive functions in Japanese chronic schizophrenia patients.

OBJECTIVE: We hypothesized that an excessive dose of antipsychotic drug and/or a larger number of antipsychotic drug worsens cognitive functions in schizophrenia patients. To confirm the hypothesis, we compared several cognitive functions in the patients taking a second-generation antipsychotic drug (SGA) only (SGA monotherapy group) with those in patients taking more than two kinds of antipsychotic drugs (polypharmacy group). METHODS: The cognitive functions of 136 chronic schizophrenia patients were evaluated using the Brief Assessment of Cognition in Schizophrenia, Japanese-language version (BACS-J). RESULTS: A significantly negative correlation was found between the composite score in the BACS-J and the chlorpromazine equivalence of doses of antipsychotic drugs in whole patients (r = -0.43, P < 0.001). Schizophrenia patients in the polypharmacy group had lower composite scores than those in the SGA monotherapy group in the BACS-J. No difference was observed in the composite score and the primary score in each item in the BACS-J between patients with first- plus second-generation antipsychotic drug (FGA + SGA group) and those with two kinds of SGA (SGA + SGA group). CONCLUSION: These results suggest that an excessive dose of antipsychotic drugs regardless of FGA and SGA might cause the deterioration of cognitive functions in chronic Japanese schizophrenia patients.

Plasma levels of metabolites of catecholamine in nicotine-dependent patients treated with varenicline.

INTRODUCTION: Our hypothesis is that varenicline decreases the plasma levels of catecholamine metabolites; such a decrease is associated with the main mechanisms of smoking cessation and leads to a depressive state. To confirm the hypothesis, we investigated the association of plasma homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) levels in patients with nicotine dependence in comparison with nonsmokers. METHODS: To confirm the hypothesis, we investigated the association of plasma HVA and MHPG levels in patients with nicotine dependence in comparison with nonsmokers. In addition, we also examined the plasma HVA and MHPG levels before (T0) and 8 weeks after the varenicline treatment (T8). RESULTS: Seventeen of 20 smokers (85.0%) stopped smoking during the 12 weeks of treatment. Plasma HVA levels and MHPG levels in the patients at T0 (HVA 5.1 ± 2.1 ng/ml, MHPG 2.2 ± 0.6 ng/ml) were significantly higher than those of the control group (HVA 3.0 ± 1.0 ng/ml, MHPG 1.6 ± 1.4 ng/ml; HVA p = .0012, MHPG p = .0069). In this study, the plasma HVA and MHPG levels were not changed after treatment with varenicline, although the smokers had already quit. CONCLUSIONS: These results suggest that varenicline sustains higher catecholamine levels. The findings that the treatment with varenicline did not decrease the plasma levels of catecholamine metabolites can explain why none of the smokers had become depressed after the varenicline treatment.

Varenicline does not increase serum BDNF levels in patients with nicotine dependence.

Varenicline, alpha4beta2 nicotinic acetylcholine receptor (nAChR) partial agonist, is a new class of medications for treating nicotine dependence. As an alpha4beta2 nAChR partial agonist, varenicline serves to reduce nicotine withdrawal symptoms, while high-affinity binding of the agonist mitigates the reinforcing effects of smoking. In the present study, we compared serum brain-derived neurotrophic factor (BDNF) levels of nicotine dependence and nonsmokers, and we investigated changes in serum BDNF levels after 8 weeks of treatment with varenicline. Patients met the DSM-IV criteria for nicotine dependence. Both the Fagerström test for nicotine dependence (FTND) and the Tobacco Dependence Screener (TDS) were used. Serum BDNF levels and breath carbon monoxide (CO) levels were measured before and 8 weeks after varenicline treatment. Fourteen of 16 subjects (87.5%) stopped smoking within 12 weeks of varenicline treatment. Thirteen healthy nonsmokers who never had previously smoked were randomly selected as a control group. Serum BDNF levels of patients before treatment (4.8 +/- 3.8 ng/ml) were significantly lower than those in the control group (12.4 +/- 6.13 ng/ml). Serum BDNF levels had not increased from baseline (4.8 +/- 3.8 ng/ml) to 8 weeks after varenicline treatment (3.0 +/- 1.1 ng/ml) of patients. These results suggest that smoking might decrease serum BDNF levels and that treatment with varenicline for 8 weeks, combined with 12 weeks of not smoking, does not increase serum BDNF levels in smokers.

Plasma levels of brain-derived neurotrophic factor and interleukin-6 in patients with dysthymic disorder: comparison with age- and sex-matched major depressed patients and healthy controls.

In the present study, we investigated the serum BDNF levels and plasma IL-6 levels in patients with dysthymic disorder, major depressive disorder and control subjects. Eighteen patients who met the DSM-IV criteria (American Psychiatric Association, 1994) for dysthymic disorder (male/female: 5/13; age: 36 ± 9 year) and 20 patients (male/female: 7/13; age: 38 ± 10 year) who met the criteria for major depressive disorder were enrolled. The serum BDNF levels in patients with dysthymic and major depressive disorder were significantly lower than those in the control subjects. However, no difference was found between the dysthymic group and major depression group. The plasma IL-6 levels in the dysthymic group and major depression group were significantly higher than those in the control group. No difference was observed in the plasma IL-6 levels between the dysthymic group and major depression group. These results suggest that the pathophysiology of dysthymic disorder and major depression might be similar in terms of the blood levels of BDNF and IL-6.

Higher plasma interleukin-6 (IL-6) level is associated with SSRI- or SNRI-refractory depression.

In the present study, we compared plasma levels of interleukin-6 (IL-6), tumor necrosis factor-alpha(TNFalpha), and brain-derived neurotrophic factor (BDNF) among selective serotonin reuptake inhibitor (SSRI)- or serotonin noradrenaline reuptake inhibitor (SNRI)-responsive depressed patients (n=31), SSRI- or SNRI-refractory depressed patients (n=20), and healthy controls (n=30). The plasma levels of IL-6 and TNF-alpha were significantly higher in depressed patients than in healthy controls. Treatment with antidepressants significantly reduced plasma levels of IL-6 and TNF-alpha. In addition, the plasma IL-6 level, but not the plasma TNF-alpha level, was higher in SSRI-refractory than SSRI-responsive depressed patients, and higher in SNRI-refractory than SNRI-responsive depressed patients. On the other hand, the plasma BDNF level was significantly lower in depressed patients than in healthy controls, whereas no difference was found in plasma BDNF levels between SSRI-responsive and -refractory depressed patients or between SNRI-responsive and -refractory depressed patients. These results suggest that higher plasma IL-6 activity is associated with the refractoriness of depression, and plasma IL-6 levels might be a predictor for response to SSRIs or SNRI.