Published papers

Purpose/Background Although discontinuing antipsychotics clearly increases the risk of relapse in schizophrenia, some patients remain clinically well without continuous antipsychotic treatment. However, data on the characteristics of such patients are still scarce. Methods/Procedures A systematic literature review was conducted to identify predictive factors for successful antipsychotic discontinuation in schizophrenia using PubMed (last search; June 2018) with the following search terms: (antipsychotic∗ or neuroleptic) AND (withdraw∗ or cessat∗ or terminat∗ or discontinu∗) AND (schizophreni∗ or psychosis). The search was filtered with humans and English. Factors associated with a lower risk of relapse, when replicated in 2 or more studies with a follow-up period of 3 months or longer, were considered successful. Findings/Results Systematic literature search identified 37 relevant articles. Mean relapse rate after antipsychotic discontinuation was 38.3% (95% confidence interval = 16.0%-60.6%) per year. Factors associated with a lower risk of relapse were being maintained on a lower antipsychotic dose before discontinuation, older age, shorter duration of untreated psychosis, older age at the onset of illness, a lower severity of positive symptoms at baseline, better social functioning, and a lower number of previous relapses. Implications/Conclusions Although this literature review suggests some predictors for successful antipsychotic withdrawal in patients with schizophrenia, the very limited evidence base and unequivocally high relapse rates after discontinuation must remain a matter of serious debate for risk/benefit considerations.

Aim: While emotional processing is implicated in various psychiatric illnesses, its differences among diagnoses are unclear. We compared associative learning of social values in patients with depression and schizophrenia by measuring skin conductance response to interpersonal stimuli. Methods: We included 20 female outpatients each with depression and schizophrenia. They underwent Pavlovian conditioning experiments in response to a classical aversive sound, and an interpersonal stimulus that was designed to cause aversive social conditioning with actors’ faces coupled with negative verbal messages. Multiple regression analysis was performed to examine the associations between the degree of conditioned response and the clinical characteristics of the participants. Results: Conditioned responses during the acquisition phase in both conditions were higher in depression compared to schizophrenia. Patients with depression successfully showed fear conditioning in both conditions, and they exhibited slower extinction in the interpersonal condition. The conditioned response during the extinction phase showed a positive association with Emotion Regulation Questionnaire Expressive Suppression score, and a negative association with the Emotion Regulation Questionnaire Cognitive Reappraisal score and the use of antidepressants. Patients with schizophrenia did not become conditioned in either of the conditions. The Positive and Negative Syndrome Scale Negative Syndrome score was negatively associated with the degree of conditioned response during the acquisition phase in the interpersonal condition. Conclusion: Female patients with schizophrenia, especially those who prominently demonstrated negative symptoms, suggested their intrinsic impairments in the associative learning of social context. Antidepressants and adaptive emotional regulation strategy may enhance the extinction learning of aversive social conditioning in depression.

Introduction: While patients’ perspectives toward pharmacotherapy are expected to be directly influenced by their motivation and understanding of the treatment that they are currently receiving, no study has comprehensively investigated the impact of insight into illness and knowledge for the ongoing pharmacotherapy on the attitude towards drug treatment among patients with schizophrenia. Materials and Methods: One hundred forty-eight Japanese outpatients diagnosed with schizophrenia, according to the International Classification of Diseases 10th edition, were included (mean±SD age, 47.3±12.4 years; 90 men (60.8%)). Attitudes toward antipsychotic treatment and insight into illness were assessed with the Drug Attitude Inventory-10 (DAI-10) and the VAGUS, respectively. In addition, a multiple-choice questionnaire that was designed to examine patients’ knowledge about therapeutic effects, types, and implicated neurotransmitters of antipsychotic drugs they were receiving was utilized. Results: The mean±SD of DAI-10 score was 4.7±4.2. The multiple regression analysis found that lower Positive and Negative Syndrome Scale (PANSS) scores, higher VAGUS scores, and longer illness duration were significantly associated with higher DAI-10 scores (β=−0.226, P=0.009; β=0.250, P=0.008; β=0.203, P=0.034, respectively). There was a significant difference in the DAI-10 scores between the subjects who gave more accurate answers regarding the effects of their primary antipsychotic and those who did not (mean ±SD, 5.57±4.38 vs 4.13±4.04, P=0.043); however, this finding failed to survive the multiple regression analysis. Conclusion: Better insight into illness and treatment, lower illness severity, longer illness duration, and possibly greater knowledge about the therapeutic effects of medications may lead to better attitudes towards pharmacotherapy among patients with schizophrenia, which has an important implication for this typically chronic mental condition requiring long-term antipsychotic treatment to sustain stability.

Introduction There has been no consensus on whether and how long add-on drugs for augmentation therapy should be continued in the treatment of depression. Methods Double-blind randomized controlled trials that examined the effects of discontinuation of drugs used for augmentation on treatment outcomes in patients with depression were identified. Meta-analyses were performed to compare rates of study withdrawal due to any reason, study-defined relapse, and adverse events between patients who continued augmentation therapy and those who discontinued it. Results Seven studies were included (n=841 for continuing augmentation therapy; n=831 for discontinuing augmentation therapy). The rate of study withdrawal due to any reason was not significantly different between the 2 groups (risk ratio [RR]=0.86, 95% confidence interval [CI]=0.69-1.08, p=0.20). Study withdrawal due to relapse was less frequent in the continuation group than in the discontinuation group (RR=0.61, 95% CI=0.40-0.92, p=0.02); however, this statistical significance disappeared when one study using esketamine as augmentation was excluded. Analysis of the data from 5 studies that included a stabilization period before randomization found less frequent relapse in the continuation group than in the discontinuation group (RR=0.47, 95% CI=0.36-0.60, p<0.01). This finding was repeated when the esketamine study was excluded. Discussion No firm conclusions could be drawn in light of the small number of studies included. Currently available evidence suggests that add-on drugs, other than esketamine, used for augmentation therapy for depression may be discontinued. This may not be the case for patients who are maintained with augmentation therapy after remission.

This systematic review and meta-analysis examined predictors of successful antipsychotic dose reduction in schizophrenia. Prospective clinical trials and randomized controlled trials (RCTs) investigating antipsychotic dose reduction in schizophrenia were selected for systematic review and meta-analysis, respectively. In total, 37 trials were identified. Only 8 studies focused on second-generation antipsychotics (SGAs); no studies investigated long-acting injectable SGAs. Of 24 studies evaluating relapse or symptom changes, 20 (83.3%) met the criteria for successful dose reduction. Factors associated with successful dose reduction were study duration < 1 year, age > 40 years, duration of illness > 10 years, and post-reduction chlorpromazine equivalent (CPZE) dose > 200 mg/day. Clinical deterioration was mostly re-stabilized by increasing the dose to the baseline level (N = 7/8, 87.5%). A meta-analysis of 18 RCTs revealed that relapse rate was significantly higher in the reduction group than the maintenance group (risk ratio [RR] = 1.96; 95% confidence interval [CI], 1.23–3.12), whereas neurocognition was significantly improved (standardized mean difference = 0.69; 95% CI, 0.25–1.12). A subgroup analysis indicated that only a post-reduction CPZE dose ≤ 200 mg/day was associated with an increased risk of relapse (RR = 2.79; 95% CI, 1.29–6.03). Thus, when reducing antipsychotic doses, clinicians should consider the long-term risk of relapse in younger patients with a relatively short illness duration and keep the final doses higher than CPZE 200 mg/day. Further studies, particularly those involving SGAs, are warranted to determine the optimal strategies for successful antipsychotic dose reduction in schizophrenia.

Background: While recent meta-analyses have reported the superiority of antipsychotic polypharmacy (APP) over antipsychotic monotherapy (APM) in schizophrenia, switching to APM can be beneficial in terms of side effects. To determine whether patients receiving APP should switch to APM or stay on APP, we conducted a systematic review and meta-analysis. Methods: Randomized controlled trials (RCTs) examining a switch from APP to APM vs. staying on APP were systematically selected from a previous meta-analysis comparing APP with APM in patients with schizophrenia. In addition, we conducted an updated systematic literature search using MEDLINE, Embase, and Cochrane Central Register of Controlled Trials. Data on study discontinuation, relapse, psychopathology, neurocognition, extrapyramidal symptoms, and body weight/body mass index (BMI) were extracted and synthesized. Results: A total of 6 RCTs involving 341 patients were included. All studies examined a switch from 2 antipsychotic agents to a single agent. Clozapine-treated patients were included in 3 studies. There was a significant difference in study discontinuation due to all causes in favor of staying on APP (N = 6, n = 341, RR = 2.28, 95% CI = 1.50–3.46, P < 0.001). There were no significant differences in relapse, any psychopathology, neurocognition, extrapyramidal symptoms, or body weight/BMI between the 2 groups. The quality of evidence was low to very low. Conclusions: The findings suggest that clinicians should closely monitor patient condition when switching to APM after receiving 2 antipsychotics. Given the low to very low overall quality of the evidence, the findings should be considered preliminary and inconclusive.

Although aberrations in the number and function of glutamate AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors are thought to underlie neuropsychiatric disorders, no methods are currently available for visualizing AMPA receptors in the living human brain. Here we developed a positron emission tomography (PET) tracer for AMPA receptors. A derivative of 4-[2-(phenylsulfonylamino)ethylthio]-2,6-difluoro-phenoxyacetamide radiolabeled with 11C ([11C]K-2) showed specific binding to AMPA receptors. Our clinical trial with healthy human participants confirmed reversible binding of [11C]K-2 in the brain according to Logan graphical analysis (UMIN000020975; study design: non-randomized, single arm; primary outcome: dynamics and distribution volumes of [11C]K-2 in the brain; secondary outcome: adverse events of [11C]K-2 during the 4–10 d following dosing; this trial met prespecified endpoints). In an exploratory clinical study including patients with epilepsy, we detected increased [11C]K-2 uptake in the epileptogenic focus of patients with mesial temporal lobe epilepsy, which was closely correlated with the local AMPA receptor protein distribution in surgical specimens from the same individuals (UMIN000025090; study design: non-randomized, single arm; primary outcome: correlation between [11C]K-2 uptake measured with PET before surgery and AMPA receptor protein density examined by biochemical study after surgery; secondary outcome: adverse events during the 7 d following PET scan; this trial met prespecified endpoints). Thus, [11C]K-2 is a potent PET tracer for AMPA receptors, potentially providing a tool to examine the involvement of AMPA receptors in neuropsychiatric disorders.