論文

Although recent treatment guidelines for schizophrenia recommend that the prior antipsychotic agent should remain stable for at least 2 weeks when aripiprazole is introduced, there is no trial-based evidence to support this strategy. This study was designed to compare this strategy with another conventional one in patients with schizophrenia. We conducted a randomized, 14-week, open-label trial to compare the following 2 switching strategies: (1) add-on of aripiprazole on a current regimen, wait for 4 weeks, and the tapering of prior antipsychotics and (2) add-on of aripiprazole and the simultaneous tapering of prior antipsychotics in patients with schizophrenia. Aripiprazole was initiated at 12 mg/d and then titrated between 12 and 30 mg. The previous antipsychotic medication was reduced biweekly by 25%. Assessments included the Clinical Global Impression Scale Schizophrenia version, the Drug-Induced Extrapyramidal Symptoms Scale, and the Subjective Well-being Under Neuroleptics, Short Version, Japanese Edition. Impressions toward their assigned strategy were also subjectively evaluated at baseline and end point. Fifty-three patients were enrolled, and 48 patients completed this trial. No significant differences were found in changes from the baseline in the total Clinical Global Impression Scale Schizophrenia version severity, Drug-Induced Extrapyramidal Symptoms Scale, and Subjective Well-being Under Neuroleptics, Short Version, Japanese Edition scores throughout the study period between the 2 strategies. Both strategies were judged by subjects to be tolerable and favorable without between-group differences. In conclusion, both strategies were found to be objectively safe and well tolerated. Taken together with similar results from subjective assessments, it would be reasonable to choose either of these 2 strategies in clinical practice based on a patients' preference.

Objective: Long-acting risperidone administered intramuscularly biweekly is approved for the management of schizophrenia. However, dosing of long-acting antipsychotics is frequently extended in clinical practice, and a recent clinical trial has lent support to monthly dosing of long-acting risperidone. The objective of this positron emission tomography (PET) study was to examine the striatal dopamine D2 binding of long-acting risperidone administered intramuscularly once a month. Method: Following at least 3 maintenance monthly injections of 50 mg long-acting risperidone, 7 patients with a DSM-IV diagnosis of schizophrenia or schizoaffective disorder underwent PET using [11C]raclopride to measure D2 binding potential within 4 days of the next scheduled injection. Data were collected from May to October 2003. This PET study was part of a larger 52-week clinical study wherein individuals received long-acting risperidone once monthly over a 1-year interval. One-year follow-up data were obtained from the 52-week parent investigation. Results: The mean ± SD D2 receptor occupancy was 56% ± 24% (range, 29%-82%). Of note, there were 4 subjects with less than 60% D2 occupancy, none of whom relapsed over the course of the 1-year follow-up. The mean ± SD total plasma level of risperidone plus 9-hydroxyrisperidone was 16.6 ± 12.3 ng/mL (range, 5.7-40.8). Conclusion: As with plasma levels, there was considerable variability in D2 occupancy levels for individuals receiving long-acting risperidone. This work suggests a possibility that sustained D2 occupancy at or above the accepted threshold with acute clinical response may not be necessary to maintain response, a hypothesis with important clinical implications as we consider antipsychotic dosing and future antipsychotic development. Trial Registration: clinicaltrials.gov Identifier: NCT00236353

Objective: To evaluate the effectiveness of antipsychotic polypharmacy in a methodologically sound manner. Methods: In this open-label study, 17 patients with treatment-refractory schizophrenia, who failed to respond to a sequential monotherapy with olanzapine, quetiapine and risperidone, were subsequently treated with a combination therapy with olanzapine plus risperidone for at least 8 weeks. Results: Seven responded according to the primary endpoint defined as the post-treatment Brief Psychiatric Rating Scale being less than 70% of the pretreatment values, and they were classified as such an average of 10 weeks after the initiation of polypharmacy. Two of them were successful in a later conversion to monotherapy. None dropped out prematurely. Four (out of 13 inpatients) got better enough to be discharged from the hospital, while six patients did not show any response. The Global Assessment of Functioning score improved from 37.1 to 53.0 in responders (mean maximum dose: olanzapine 12.9 mg; risperidone 3.14 mg), while it showed non-significant changes among others (mean maximum dose: olanzapine 14.5 mg; risperidone 5.50 mg). Body weight, prolactin, and total cholesterol increased significantly. Conclusions: Antipsychotic polypharmacy might be sometimes helpful for difficult populations but at the cost of adverse effects. More studies of antipsychotic combination therapy versus clozapine, augmentation strategies or tenacious longer-term monotherapy are warranted for refractory schizophrenia.

The relationship between age and prescribed antipsychotic dose in patients with schizophrenia has been examined by assuming only a linear correlation in two age subgroups at most. The age of illness onset has also not been under adequate consideration in past prescription surveys. The objective of this study was to better evaluate these age effects on antipsychotic dose prescribed in these patients across a broad age range. Methods: Review of prescriptions for antipsychotic medications in patients with schizophrenia spectrum disorders was conducted across 30 sites in Tokyo. A total of 1,418patients (655 inpatients, 763 males, age range: 16.6-90.2 years) were studied. Results: Age had significant effects on prescribed antipsychotic dose; the dose increased with age through the third decade, subsequently plateaued, and decreased after the fifth decade. The age of illness onset also had significant effects on the dose; late-onset schizophrenia (LOS) and very-late-onset schizophrenia-like psychoses (VLOS) patients received lower doses than early onset schizophrenia (EOS) patients. LOS and VLOS patients who did not experience any hospitalization for the previous year were treated with 1/2 and 1/3, respectively, of the dose for EOS of comparable current age. Conclusion: Our results suggested biphasic effects of age on antipsychotic dose prescribed in patients with schizophrenia spectrum disorders. The natural history of schizophrenia and physiological aging may contribute to this inverted U-shaped relationship. In addition, our results may add another evidence of dis-ttnction among EOS, LOS, and VLOS from a clinical psychopharmacological perspective.

Objective: The pharmacokinetic and pharmacodynamic profile of the immediate-release (IR) formulation of quetiapine is characterized by a rapid peak in plasma level and striatal dopamine D2 receptor occupancy, followed by a rapid decrease to baseline levels, necessitating the use of twice-daily dosing. An extended-release (XR) formulation of quetiapine is currently being developed to achieve similar efficacy using a once-daily dosing regimen. We compared the central D2 receptor binding between the IR and XR formulations. Method: In this open-label, crossover positron emission tomography study using [11C]-raclopride, we compared the central D2 receptor binding potential at expected peak and trough plasma levels using equivalent daily doses of the IR and XR formulations (300, 600, and 800 mg/day) in 12 subjects. Data were collected from April 2002 to May 2003. Results: The mean plasma level of quetiapine at trough was significantly lower than that at peak for all dose groups of both formulations except for IR 300 and 800 mg (all p values < .05), while the mean plasma level did not differ significantly between formulations at trough and peak. The mean occupancy at peak was significantly higher than that at trough for all dose groups other than IR 800 mg/day (all p values < .05) and did not differ significantly between formulations at trough and peak. Conclusion: Once-daily dosing of the XR formulation gives peak and trough plasma levels and central D2 receptor occupancy comparable to twice-daily dosing of the IR formulation. These data should be considered while determining equivalent doses, as well as switching strategies.

Objective: To report the usefulness of antipsychotic dose-reduction for avoiding paralytic ileus in a patient with chronic schizophrenia and comorbid dementia. Case summary: A 65-year-old in-patient developed severe paralytic ileus warranting a transfer to the general hospital. Constipation was very troublesome and he often needed enema to prevent intestinal obstruction. He had originally been treated with 24 mg of bromperidol, which was reduced to 4 mg, and other psychotropic treatments were simultaneously simplified. As a result, bowel habits improved and enema is now only rarely necessary. Constipation is a frequent adverse effect of antipsychotics and adjunctive psychotropics, which can be severe and may lead to life-threatening paralytic ileus. Dose-reduction obviated a necessity of enema against persistent constipation, while the patient's mental status remained under control. Assessment using the Naranjo probability scale revealed a definite causal relationship. Discussion: With an increasing number of elderly patients with schizophrenia, more cases of severe gastrointestinal motility problems from antipsychotic medication are to be expected. In this patient population dose-reduction of antipsychotics and simplification of concomitant psychotropics should be seriously considered.

There are sporadic reports of antipsychotic-induced visual hypersensitivity attack (VHA). VHA is characterized by hypersensitivity of perception mainly in the visual modality and sometimes accompanied by an oculogyric crisis. However, some researchers regard VHA as a schizophrenia symptom. To determine whether VHA is an adverse effect of antipsychotic agents, we examined the effect of dose reduction on VHA. This was an open-label 36-week study. We randomized 34 patients with VHA to a reduced-dose group and a fixed-dose group. Primary outcome measures were the frequency and duration of VHA, assessed with patients' self-reports, and the Clinical Global Impressions (CGI). Assessment also included the Drug-induced Extrapyramidal Symptoms Scale for extrapyramidal symptoms, the Positive and Negative Syndrome Scale (PANSS) for schizophrenia, and the CGI for other diagnoses. Data were collected from August 2000 to April 2005 at 4 psychiatric hospitals in Tokyo. VHA diminished in 16 patients (94.1%) in the reduced-dose group in the CGI score, the frequency (number of episodes per week), and the duration of the episodes (from 4.06 to 1.77, P < 0.001; from 2.59 to 0.82, P = 0.001; and from 1.92 to 0.66 hours, P = 0.007, respectively), but there were no changes in the fixed-dose group. There were no changes in the underlying illness as measured by the PANSS in both groups. Reducing the dose of antipsychotic agents ameliorates VHA and represents the ideal treatment option for patients with VHA.

Aspiration pneumonia is a serious health concern in older patients with schizophrenia. In this study, we examined clinical and demographic variables that could impact the plasma substance P level, which is a useful predictive biomarker of aspiration. Thirty-four patients were included (mean age ± SD: 70.9 ± 10.8 years). A greater number of cigarettes/day and a higher antipsychotic dosage were found to be associated with a lower plasma substance P level, while age showed a trend-level effect. This finding suggests the need for intensive observation for prevention of aspiration pneumonia in heavy smokers who are receiving a higher antipsychotic dose in this senior population.

Positron emission tomography (PET) studies proposed a therapeutic window of D2 receptor occupancy (65%-80%) of antipsychotics for the treatment of schizophrenia in young adults. However, this conclusion has been drawn from clinical PET studies using small sample sizes (<20). Prospective PET studies that measured D2 occupancy levels and assessed extrapyramidal side effects (EPS) and/or treatment response induced by antipsychotics (excluding partial agonists) were identified, using MEDLINE and EMBASE (last search: March 2010). Individual subjects were divided into 2 groups based on EPS status (ie, presence or lack of newly emergent EPS) and treatment response (ie, a ≥ 25% or ≥ 50% reduction in the Positive and Negative Syndrome Scale or Brief Psychiatric Rating Scale). To evaluate the performance of this binary classification, sensitivity, specificity, and accuracy of consecutive cutoff points in the D2 occupancy were calculated: Accuracy = (True Positive + True Negative)/Total N. Twelve studies, including a total of 82 subjects, were included in our analyses. The cutoff points associated with 0.5 or greater in both sensitivity and specificity with the greatest accuracy were 77% to 78% for EPS, 60% for a 25% or greater symptom reduction, and 72% for a 50% or greater symptom reduction. These findings support the presence of a therapeutic window of 60% to 78% D2 occupancy of antipsychotics in young adults with schizophrenia and may suggest the presence of a continuum of effectiveness with increasing occupancy within this therapeutic window.

Background: It remains unknown as to whether the antipsychotic dose needed for the acute-phase treatment of schizophrenia is also necessary for relapse prevention. Aim: To compare the efficacy between standard dose [(World Health Organization daily defined dose (DDD)] vs low dose (≥50% to <1 DDD) or very low dose (<50% DDD) for relapse prevention in schizophrenia. Data source: Double-blind, randomized, controlled trials with a follow-up duration of ≥24 weeks, including ≥2 dosage groups of the same antipsychotic drug for relapse prevention in schizophrenia, were searched using MEDLINE, the Cochrane Central Register of Controlled Trials, and EMBASE (last search: August 2009). Data extraction: Data on overall treatment failure, hospitalization, relapse, and dropouts due to side effects were extracted and combined in a meta-analysis. Data synthesis: Thirteen studies with 1395 subjects were included in this meta-analysis. Compared with the standard-dose treatment, the low-dose therapy did not show any statistically significant difference in overall treatment failure or hospitalization, while the standard dose showed a trend-level (P =. 05) superiority in risk of relapse. The very low-dose group was inferior to the standard-dose group in all efficacy parameters. No significant difference was found in the rate of dropouts due to side effects between either standard dose vs low dose or very low dose. Conclusions: Although antipsychotic treatment with ≥50% to <1 DDD may be as effective as standard-dose therapy, there are insufficient clinical trial data to draw firm conclusions on standard- vs low-dose maintenance antipsychotic therapy for schizophrenia.

Measuring dopamine D2 receptor occupancy levels using positron emission tomography (PET) is still widely unavailable. The objective of this study was to evaluate the accuracy of predicting D2 occupancy from the antipsychotic plasma level in patients with schizophrenia. Positron emission tomographic studies that measured plasma levels of antipsychotics and their corresponding D2 occupancy levels were identified, using MEDLINE and EMBASE (last search: March 2010). Antipsychotics that were investigated in a total of 20 subjects or more were included. All data points for each antipsychotic were fit to a one-site binding model to estimate the total plasma concentration of each antipsychotic associated with a 50% occupancy (ED50) of brain D2 receptors. The mean prediction error and the root mean squared prediction error were used to measure the predictive performance of individual D2 receptor occupancies from plasma drug levels derived from a one-site occupancy model using an ED50 value calculated for each data point. A total of 34 treatment arms from 23 studies involving 281 subjects were included. The mean (95% confidence interval) prediction errors and root squared prediction errors were as low as 0.0 (-1.8 to 1.8) and 8.9 (7.6-10.2) for risperidone (n = 98); 0.0 (-3.5 to 3.5) and 15.1 (12.9-17.3) for clozapine (n = 75); -0.1 (-1.2 to 1.2), 0.0 (-1.9 to 1.9), and 4.6 (3.5-5.8) for olanzapine (n = 42); 0.1 (-3.4 to 3.5) and 9.9 (7.3-12.5) for haloperidol (n = 35); and -0.1 (-3.3 to 3.1) and 12.3 (8.8-15.7) for ziprasidone (n = 31), respectively. These findings suggest that D2 occupancy of antipsychotics could be estimated with a high degree of accuracy using widely available plasma levels.

Patients' attitudes toward side effects of antidepressants are likely to differ according to gender, which has not yet been fully addressed in the literature. From the 228,310 registrants, 1,305 participants who had received antidepressant drugs within the past year were identified with the Yahoo Japan research monitor through four-step screening procedures. Participants were asked as to which side effect(s) they had experienced, whether they had reported those side effects to their physicians, and whether they had taken any action to counteract them. The questionnaire was completed by 1,187 participants. Side effects were reported in 73.4% of the participants; the prevalence of self-reported side effects was significantly higher in men than women (80.4% vs. 68.3%, P <0.05). The percentage of participants who reported side effects to their physicians widely differed depending on the nature of their experience, ranging from 45.7% to 89.9%; the lowest was for sexual dysfunction. The percentage of participants who had taken any action to relieve side effects varied among side effects from 26.3% for sexual dysfunction to 89.5% for dry mouth. Moreover, a lower percentage of women had reported sexual dysfunction to physicians (36.6% vs. 60.7%, P <0.05) and had taken any action to counteract the problem (19.8% vs. 36.9%, P <0.05). Given that patients experienced with antidepressants are likely to be reluctant to report sexual side effects, physicians should be cognizant of the potential presence of sexual dysfunction in patients who are taking antidepressants, especially for women.