Perceived parenting before adolescence and parity have direct and indirect effects via depression and anxiety on maternal-infant bonding in the perinatal period.

AIM: This study was aimed towards detecting how perceived parenting practices before adolescence affect maternal-infant bonding in the perinatal period, considering factors such as depression, anxiety, and parity. METHODS: We used the Parental Bonding Instrument (PBI) to examine perceived parenting practices. Participants included 1301 pregnant women who completed the Hospital Anxiety and Depression Scale (HADS) and Mother-to-Infant Bonding Scale (MIBS) at three time points: early pregnancy (approximately 12-15 weeks), late pregnancy (approximately 30-34 weeks) and postpartum (4 weeks after childbirth). We performed a path analysis with factors including parity, PBI subscales (paternal care, paternal overprotection, maternal care and maternal overprotection), HADS and MIBS. RESULTS: Perceived paternal or maternal low care parenting predicted higher HADS and MIBS scores in early pregnancy. Moreover, perceived maternal low care parenting predicted higher HADS scores at postpartum and higher MIBS scores in late pregnancy. Perceived paternal or maternal overprotective parenting predicted higher HADS scores in the pregnancy period. Furthermore, perceived maternal overprotective parenting predicted higher MIBS scores in late pregnancy. Being primipara predicted higher HADS scores at postpartum and higher MIBS scores in early pregnancy and at postpartum. Being multipara predicted higher MIBS scores in late pregnancy. CONCLUSION: This study suggests that perceived negative parenting before adolescence has indirect effects (via anxiety and depression) and direct effects on maternal-infant bonding in the perinatal period.

Lower Prolactin Levels in Patients Treated With Aripiprazole Regardless of Antipsychotic Monopharmacy or Polypharmacy.

BACKGROUND: Hyperprolactinemia is a troublesome adverse effect of antipsychotics. Aripiprazole (ARP), which is one of second-generation antipsychotics, has been reported to lower serum prolactin (PRL) levels. However, few studies have compared the effect of ARP on plasma PRL levels between monopharmacy and polypharmacy with antipsychotics. METHODS: We conducted a large-scale investigation of the physical risk for inpatients with schizophrenia using a questionnaire covering demographic data, the number, dose and type of antipsychotics, and serum PRL levels. RESULTS: Sufficient data to conduct an assessment of the effect on PRL levels between antipsychotic monopharmacy and polypharmacy were obtained from 316 of the inpatients. Serum PRL levels in ARP combination group were lower than non-ARP combination group, regardless of antipsychotic monopharmacy or polypharmacy. CONCLUSIONS: The present study suggests that ARP lowers serum PRL levels regardless of monopharamacy or polypharmacy with antipsychotics.

A case report of psychiatric symptoms following direct-acting antiviral and ribavirin combination therapy for chronic hepatitis C in a patient with innate anxiety.

BACKGROUND: Direct-acting antivirals (DAAs) result in a highly sustained virological response rate and better patient tolerance. However, this therapeutic approach may, on rare occasions, give rise to psychiatric symptoms. We describe a case requiring discontinuation of DAA and ribavirin combination therapy due to psychiatric symptoms in a patient with congenital anxious personality traits. The information summarized here will be helpful to physicians treating chronic hepatitis C virus (HCV) infection in patients with underlying psychiatric problems. CASE PRESENTATION: A 57-year-old Japanese woman diagnosed with chronic HCV infection was prescribed DAA and ribavirin combination therapy. She had a history of mild innate anxiety and development of psychiatric symptoms due to interferon (IFN) therapy 8 years prior, which subsided with discontinuation of the therapy. Similar psychiatric symptoms such as enervation, palpitations, an episode of hyperventilation, and consciousness disturbances with myotonia were observed after the administration of the antiviral agents. No abnormal findings related to her symptoms were observed on laboratory or imaging results. Psychiatrists diagnosed the patient as having a somatization disorder induced by the antiviral agents on the basis of innate anxiety. After the discontinuation of therapy, her symptoms gradually improved. CONCLUSIONS: Although DAAs were not causative factors for psychiatric symptoms in phase 3 studies, a post-marketing study reported psychiatric symptoms such as depression in patients with underlying psychiatric problems. Our case suggests psychiatric symptoms might worsen after DAA and ribavirin administration in patients with underlying psychiatric disorders, and therefore, close monitoring is necessary for these patients, especially if they have a history of psychiatric symptoms after IFN.

High-density lipoprotein-cholesterol and antipsychotic medication in overweight inpatients with schizophrenia: post-hoc analysis of a Japanese nationwide survey.

BACKGROUND: Patients with schizophrenia have an increased prevalence of metabolic disturbances compared with the general population. However, the mechanisms underlying the metabolic side effects of antipsychotics are unknown. The aim of the present study was to compare the levels of high-density lipoprotein (HDL)-cholesterol in Japanese schizophrenia patients medicated with olanzapine, risperidone, or aripiprazole monotherapy. METHODS: This study was a post-hoc analysis of a nationwide survey, which included 433 Japanese outpatients with schizophrenia and 674 inpatients. A brief questionnaire was compiled that covered demographic data, systolic blood pressure, diastolic blood pressure, and HDL-cholesterol after reviewing the relevant literature and guidelines. To compare demographic and clinical characteristics, analysis of variance was performed for continuous variables and the chi-square test was performed for categorical variables. For comparisons of HDL-cholesterol levels among the three antipsychotic groups, analysis of covariance was carried out with age, diastolic blood pressure, chlorpromazine-equivalent dosage, and waist circumference as confounding variables after stratification by body mass index (BMI) for each outpatient group and inpatient group. RESULTS: The mean age was 57.9 ± 14.0 years and the mean BMI was 23.4 ± 4.5 kg/m2. HDL-cholesterol levels when stratified by BMI differed significantly (p = 0.019) between the three antipsychotic groups after age, diastolic blood pressure, chlorpromazine-equivalent dosage, and waist circumference in inpatients. A significant difference in HDL-cholesterol levels was only found in the overweight inpatient group, and no significant differences in HDL-cholesterol levels were found among the three antipsychotics for outpatients of all BMI stratifications or inpatients that were underweight or of normal weight. For post-hoc analysis of HDL-cholesterol levels in overweight inpatients, HDL-cholesterol was significantly lower in the olanzapine group than in the aripiprazole group (p = 0.023). CONCLUSIONS: This study reveals a difference in HDL-cholesterol levels in overweight Japanese inpatients with schizophrenia resulting from the use of different antipsychotics. In the post-hoc analysis of HDL-cholesterol levels in overweight inpatients, HDL-cholesterol was significantly lower in the olanzapine group than in the aripiprazole group. Further studies incorporating more detailed evaluations, including diet and physical activity, are needed to clarify the differences in HDL-cholesterol according to antipsychotic use.

Sex Differences in the Effect of Atomoxetine on the QT Interval in Adult Patients With Attention-Deficit Hyperactivity Disorder.

BACKGROUND: The effects of atomoxetine on QT in adults remain unclear. In this study, we examined whether the use of atomoxetine to treat attention-deficit hyperactivity disorder in adults is associated with QT prolongation. METHODS: Forty-one subjects with attention-deficit hyperactivity disorder were enrolled in this study. Participants were administered 40, 80, or 120 mg atomoxetine daily and were maintained on their respective dose for at least 2 weeks. We conducted electrocardiographic measurements and blood tests, measuring plasma atomoxetine concentrations after treatment. Electrocardiograms of 24 of the patients were also obtained before atomoxetine treatment. The QT interval was corrected using Bazett (QTcB) and Fridericia (QTcF) correction formulas. RESULTS: In these 24 patients, only the female patients had prolonged QTcB (P = 0.039) after atomoxetine treatment. There was no correlation between plasma atomoxetine concentrations and the corrected QT interval (QTc), or between atomoxetine dosage and the QTc. However, in female patients, there was a significant positive correlation between atomoxetine dosage and the QTcB (r = 0.631, P = 0.012), and there was a marginally significant positive correlation between atomoxetine dosage and the QTcF (r = 0.504, P = 0.055). In male patients, there was no correlation between atomoxetine dosage and the QTcB or QTcF intervals. There was no correlation between plasma atomoxetine concentrations and the QTc in either female or male patients. IMPLICATIONS: Clinicians should exhibit caution when prescribing atomoxetine, particularly for female patients.

Effect of GWAS-Identified Genetic Variants on Maximum QT Interval in Patients With Schizophrenia Receiving Antipsychotic Agents: A 24-Hour Holter ECG Study.

BACKGROUND: Users of antipsychotics (APs) have a risk of sudden cardiac death (SCD). Sudden cardiac death in such patients is thought to be largely due to drug-induced QT prolongation. It has been reported that many subjects with drug-induced torsades de pointes (TdP) have risk alleles associated with subclinical congenital long QT syndrome. METHODS: We investigated the effects of the risk alleles associated with long QT on the QT interval in patients receiving APs using 24-hour Holter electrocardiograms to take into account the circadian fluctuation of QT intervals. We investigated 8 single-nucleotide polymorphisms identified on a GWAS. RESULTS: We found that increased numbers of risk alleles at rs7188697 in NDRG4 and rs11970286 in PLN were the major predictors of an increased maximum QT interval over 24 hours in users of APs. CONCLUSIONS: It could be useful to perform a DNA-based analysis before the initiation of APs to reduce the risk of drug-induced torsades de pointes and SCD.

GIPR Gene Polymorphism and Weight Gain in Patients With Schizophrenia Treated With Olanzapine.

Association between gastric inhibitory polypeptide receptor polymorphism, rs10423928, and body mass index in olanzapine-treated schizophrenia was examined. Body mass index change for the A/T+A/A genotypes was significantly higher than that for the T/T genotype. rs10423928 may predict weight gain in schizophrenia.

High prevalence of underweight and undernutrition in Japanese inpatients with schizophrenia.

AIMS: In Europe and North America, schizophrenia patients treated with antipsychotic agents have a higher prevalence of obesity and metabolic syndrome compared with healthy individuals. In Japan, the prevalence of overweight/obesity in the general population is considerably lower than that in Europe and North America. The purpose of this study was to investigate the prevalence of underweight and overweight/obesity as well as laboratory data in Japanese inpatients with schizophrenia. METHODS: The subjects were 333 inpatients with schizophrenia and 191 age- and sex-matched healthy volunteers. Overweight/obesity was defined as body mass index (BMI) ≥ 25 kg/m(2) , standard weight was defined as BMI ≥ 18.5 to <25 kg/m(2) and underweight was defined as BMI < 18.5 kg/m(2) . RESULTS: A significant difference in the prevalence of the three BMI levels was observed between schizophrenia patients and controls (P < 0.001). The prevalence of underweight was significantly higher in schizophrenia patients than that in controls (P < 0.001). The prevalence of hypoproteinemia (P < 0.001) and of hypocholesterolemia (P < 0.001) were significantly higher in schizophrenia patients than in controls. In schizophrenia patients, the prevalence of hypotriglyceridemia was significantly higher in the underweight group than in the standard weight group (P = 0.003) and in the overweight/obesity group (P < 0.001). CONCLUSIONS: The prevalence of underweight in Japanese inpatients with schizophrenia may be higher compared with that in the general population. Therefore, the physical health of inpatients should be more carefully taken into account in clinical practice.

Changes in PR and QTc intervals after switching from olanzapine to risperidone in patients with stable schizophrenia.

AIM: We examined the difference between the effects of olanzapine (OLZ) and risperidone (RIS) on PR and QT intervals among patients with stable schizophrenia using a cohort analysis. METHODS: Twenty-one subjects treated with OLZ were enrolled in the study. Following baseline assessments, which included PR and QT intervals, OLZ was switched to RIS for each subject. The same parameters were evaluated following the switch to RIS. RESULTS: All patients who had been treated with OLZ were successfully switched to RIS. In all patients, we observed a significant decrease in PR interval (t = 2.397, P = 0.029) and no change in either QTc or RR interval. In female patients, the QTc interval was significantly decreased (t = 3.495, P = 0.008) following the switch, while in male patients, the QTc interval did not change. No patients showed a PR interval of >200 ms or a QTc interval of >500 ms. CONCLUSION: OLZ treatment has a greater prolonging effect on PR and QT intervals compared with RIS. Careful attention may need to be paid to the cardiac conduction system in addition to QT prolongation during OLZ treatment.

Impact of the ABCB1 gene polymorphism on plasma 9-hydroxyrisperidone and active moiety levels in Japanese patients with schizophrenia.

9-Hydroxyrisperidone (9-OH-RIS) is an active metabolite of the antipsychotic drug risperidone (RIS). The total active moiety level, in other words the sum of the RIS and 9-OH-RIS serum levels, may be important for estimating the clinical effects of RIS treatment. However, there have been no consistent results reported regarding the relationship between cytochrome P450 (CYP) 2D6 or adenosine triphosphate-binding cassette subfamily B member 1 (ABCB1) variant alleles and 9-OH-RIS or total active moiety plasma levels. Seventy-four Japanese patients treated with RIS were examined in the present study. Steady-state plasma RIS and 9-OH-RIS were measured. The CYP2D6*5, CYP2D6*10, ABCB1 3435C>T, and ABCB1 2677G>T/A genotypes were detected. Multiple regression analysis showed that the dose-corrected plasma RIS levels were significantly correlated with the number of CYP2D6 variant alleles and ABCB1 3435C>T genotypes, whereas the 9-OH-RIS and total active moiety levels were significantly correlated with the ABCB1 3435C>T genotypes and with age. On the other hand, the ABCB1 2677G>T/A genotypes did not affect plasma RIS, 9-OH-RIS, or total active moiety levels. The ABCB1 3435C>T genetic polymorphism may predict plasma 9-OH-RIS and total active moiety levels.

The prevalence of glucose intolerance in Japanese schizophrenic patients with a normal fasting glucose level.

BACKGROUND: The prevalence of diabetes in patients with schizophrenia is 2- to 3-fold higher than in the general population. Glucose abnormalities were detected in 11.9% of Japanese schizophrenic patients in a recent cross-sectional study that included fasting glucose monitoring. However, detailed studies of glucose intolerance using the glucose tolerance test have been limited in Japanese patients with schizophrenia. We investigated the prevalence of abnormal glucose tolerance after glucose loading among Japanese inpatients with schizophrenia, with normal fasting glucose levels. METHOD: A total of 258 inpatients with schizophrenia participated in this study after giving their written informed consent. A 75-g oral glucose tolerance test was conducted in the morning after a 12-hour overnight fast. RESULTS: Among patients with normal fasting glucose, 81.3% had normal glucose tolerance, 17.3% had impaired glucose tolerance, and 1.3% were diagnosed with diabetes. CONCLUSIONS: This study showed that the frequency of impaired glucose tolerance in patients with schizophrenia with normal fasting glucose levels might be higher than in the general population. Careful monitoring and screening of patients with schizophrenia for abnormal glucose metabolism might therefore be necessary.

Sex differences in the effect of four second-generation antipsychotics on QTc interval in patients with schizophrenia.

OBJECTIVE: We examined sex differences in the effect of olanzapine (OLZ), risperidone (RIS), aripiprazole (ARP), or quetiapine (QTP) on mean corrected QT (QTc) intervals among 222 patients with schizophrenia. METHODS: Subjects were patients with schizophrenia who were treated with either OLZ (n = 69), RIS (n = 60), ARP (n = 62), or QTP (n = 31). Electrocardiographic measurements were conducted, and the QT interval was corrected using Bazett's correction formula. RESULTS: The mean QTc interval of the QTP group was significantly longer than that of the RIS group (p = 0.002) or ARP group (p = 0.029). The mean QTc interval of the OLZ group was also significantly longer than that of the RIS group (p = 0.006). In female participants, the difference in the mean QTc interval among the four second-generation antipsychotic (SGA) groups was statistically significant (p = 0.002), whereas in male patients, there was no significant difference in the mean QTc interval among the four SGA groups. Post hoc analyses showed that sex differences in QTc interval were observed only in OLZ treatment group (p = 0.007). CONCLUSION: To our knowledge, this is the first study to demonstrate sex differences in the effect of four SGAs on the QTc interval.

Low prevalence of metabolic syndrome and its prediction in Japanese inpatients with schizophrenia.

OBJECTIVES: There have so far been few papers studying the metabolic syndrome (MetS) prevalence rate in Japanese patients with schizophrenia. We studied the MetS prevalence rate in Japanese controls and inpatients with schizophrenia and compared the prediction factors for the occurrence of MetS. METHODS: The subjects were 319 inpatients with schizophrenia and 154 controls. The predictive utilities of body mass index (BMI) and the individual components of MetS for MetS diagnosis were evaluated. RESULTS: The prevalence of MetS did not differ between schizophrenia and control subjects. Subjects with schizophrenia showed higher prevalences of the MetS criteria for high-density lipoprotein cholesterol (HDL) (p < 0.001) and waist circumference (WC) (p < 0.001). In subjects with schizophrenia, the predictive power was found to be highest for HDL, followed by WC, BMI, triglyceride, diastolic blood pressure (BP), systolic BP and fasting plasma glucose. However, in control subjects, the predictive power was found to be highest for triglyceride, followed by WC, systolic BP, BMI, HDL, diastolic BP and fasting plasma glucose. HDL was the component most predictive of MetS in subjects with schizophrenia treated with antipsychotics. CONCLUSION: Because, in normal clinical practice, it is difficult to obtain temporal measurements for all of the MetS criteria, measurement of HDL may be useful for predicting the MetS.

Changes in QT interval after switching to quetiapine in Japanese patients with schizophrenia.

OBJECTIVES: There are few reports regarding quetiapine (QTP)-related QT prolongation. We examined the change in QT interval after switching from aripiprazole (ARP), olanzapine (OLZ), or risperidone (RIS) to QTP. METHODS: Twenty subjects treated with ARP, OLZ, or RIS were enrolled in the study. Following baseline assessments, which included QT interval and electrolytes, these three drugs were switched to QTP for each subject. The same parameters were evaluated following a switch to QTP. RESULTS: All 20 patients who had been treated with ARP, OLZ, or RIS were successfully switched to QTP. Significant increases were observed in the total mean corrected QT (QTc) interval after switching (p = 0.014). The coefficient of variation for the extent of change in QTc interval was 1.66. The mean QTc with ARP treatment was significantly increased after QTP treatment (p = 0.004). CONCLUSIONS: Quetiapine might have a greater effect on QTc interval than other second-generation antipsychotics. However, because there was a considerable variability in the extent of QTc prolongation after switch to QTP, further studies are required to clarify the effect of QTP on QTc interval.

Excessive insulin secretion in Japanese schizophrenic patients treated with antipsychotics despite normal fasting glucose levels.

The development of impaired glucose tolerance induced by antipsychotics (APs) is of concern as a serious adverse effect of psychiatric drug therapy. However, the mechanism by which APs cause dysfunction of the glucose-insulin response is not fully understood. Recent studies have shown that patients treated with APs for schizophrenia were more likely to exhibit impaired glucose tolerance after a glucose load compared with healthy control subjects, even if fasting glucose levels were within the reference range. To explain these findings, we hypothesized that insulin secretion is increased in schizophrenic patients treated with AP, even those normal fasting glucose (NFG) levels. Therefore, oral glucose tolerance tests were conducted in 159 Japanese inpatients with AP-treated schizophrenia and in 90 healthy subjects without schizophrenia. Plasma glucose and serum insulin concentrations were measured before (0 minute) and at 30, 60, 90, and 120 minutes after the oral glucose load. Although insulin levels at 0 minute were similar in both groups of subjects, insulin levels were significantly higher in the patients treated with AP at all times after the glucose load than in the healthy subjects. In analyses of NFG subjects, insulin levels were significantly higher in the patients treated with AP compared with the healthy subjects at all times after glucose loading. Overall, we found that insulin secretion in response to a glucose load was significantly higher in the patients treated with AP, irrespective of NFG. These results suggest that APs affect the glucose-insulin response, which may lead to subclinical insulin resistance before the onset of overt glucose intolerance.

Increased risk of antipsychotic-related QT prolongation during nighttime: a 24-hour holter electrocardiogram recording study.

Most antipsychotic agents can cause QT prolongation, which causes torsades de pointes. The QT interval in healthy subjects is longer during nighttime than during daytime. The QT interval of patients treated with antipsychotics may be prolonged during nighttime, and the effects of antipsychotics on the QT interval may differ between antipsychotics. This study investigated the circadian dynamics of the QT interval in patients treated with antipsychotics and healthy controls, using a 24-hour Holter electrocardiogram in a clinical setting. Sixty-six patients with a diagnosis of schizophrenia that were treated with risperidone or olanzapine and 40 healthy volunteers were enrolled. The QT intervals were corrected using the Fridericia formula (QTcF = QT / RR). Mean ± SD nighttime QTcFs were 411.6 ± 29.0, 395.9 ± 21.2, and 387.8 ± 19.0 milliseconds (ms) in the risperidone, olanzapine, and control groups, respectively. The mean daytime QTcFs were 397.7 ± 23.4, 392.4 ± 18.9, and 382.6 ± 17.3 ms, respectively. The mean nighttime QTcF of the risperidone group was significantly longer than that of the olanzapine and control groups, although there was no significant difference in the mean daytime QTcF between the risperidone and olanzapine groups. The current study used 24-hour Holter electrocardiograms to reveal significantly longer QT intervals in the risperidone group especially during nighttime. In clinical practices, evaluations of the QT interval have been conducted over short periods in the daytime, but it is believed that such methods may not be able to fully elucidate the effects of antipsychotics on the QT interval.

Dysregulation of adipocytokines related to second-generation antipsychotics in normal fasting glucose patients with schizophrenia.

OBJECTIVE: The underlying mechanism for second-generation antipsychotic (SGA)-related glucose-lipid metabolic dysfunction is not fully understood. Recent studies have suggested a possible impact of SGAs on endocrine regulation, especially on adipocytokines. We examined the effect of each SGA on various adipocytokines in normal fasting glucose (NFG) subjects. METHOD: The study population comprised 113 Japanese inpatients with schizophrenia who were treated with olanzapine, risperidone, or quetiapine, and 123 healthy control (CONT) volunteers. All of the subjects were diagnosed with NFG. Plasma concentration of adiponectin, leptin, tumor necrosis factor α, total cholesterol, triglyceride, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol were compared between the SGA and CONT groups. RESULTS: Second-generation antipsychotic subjects had significantly higher leptin levels in comparison to the CONT subjects. The plasma concentration of adiponectin, total cholesterol, and high-density lipoprotein cholesterol in the SGA subjects were significantly lower than those in the CONT subjects. There were no significant differences in tumor necrosis factor α, triglyceride, and low-density lipoprotein cholesterol levels between the 2 groups. In a stepwise multiple regression analysis, olanzapine was found to be a factor that contributed to decreased adiponectin levels, and the CONT subjects were detected to be a factor associated with lower leptin levels. CONCLUSIONS: The present study indicates the possibility that the administration of SGAs may affect adipocytokines in the NFG stage, excluding the impaired fasting glucose group, which is in the transition stage into diabetes mellitus.

Effect of the cytochrome P450 2D6*10 allele on risperidone metabolism in Japanese psychiatric patients.

OBJECTIVE: The sum of the serum levels of risperidone (RIS) and 9-hydroxyrisperidone (9-OH-RIS), which is the active moiety serum level, could be important for estimating the clinical effects of RIS. However, there have been no consistent results reported about the relationship between cytochrome P450 (CYP) 2D6*10 allele and plasma 9-OH-RIS or active moiety levels. We investigated the effect of the number of CYP2D6*10 alleles on steady-state plasma RIS, 9-OH-RIS, and active moiety levels in Japanese patients. METHODS: Steady-state plasma RIS, 9-OH-RIS, and active moiety levels were measured in 64 patients treated with an average dosage of 4.6 mg/day. RESULTS: The number of CYP2D6*10 alleles significantly affected dose-corrected plasma RIS levels (p = 0.001), and the median concentrations in ng/ml/mg were 0.94 (0 allele) vs. 1.73 (1 allele) vs. 3.05 (2 alleles). The number of CYP2D6*10 alleles did not affect plasma 9-OH-RIS or active moiety levels. CONCLUSION: The present study shows that the number of CYP2D6*10 alleles affected plasma RIS levels but not plasma 9-OH-RIS and plasma active moiety levels. Because the plasma active moiety levels can influence antipsychotic effects or side effects, the genetic screening of the CYP2D6*10 allele for RIS in Asian populations may not be clinically important.

QT prolongation of the antipsychotic risperidone is predominantly related to its 9-hydroxy metabolite paliperidone.

OBJECTIVE: A dose-dependent increase in risk of sudden cardiac death for the antipsychotic drug risperidone was reported. However, few reports have so far addressed QT prolongation associated with the use of risperidone or its major active metabolite, which is also used as a separate antipsychotic drug, paliperidone. METHODS: The present study evaluated associations between risperidone metabolism and QT interval in 61 psychiatric patients who had been receiving risperidone for ≥4 weeks at an average dosage of 4.7 mg/day. Plasma risperidone and paliperidone levels were measured and electrocardiographic measurements were also obtained. RESULTS: There was no correlation between risperidone dosage and QTc or plasma risperidone levels and QTc. However, there was a significant positive correlation between plasma paliperidone levels and QTc (r = 0.361; p = 0.004). There was no correlation between age and dose-corrected plasma risperidone levels or between age and QTc. There was a significant positive correlation between age and dose-corrected plasma paliperidone levels (r = 0.290; p = 0.023). CONCLUSION: Clinically, paliperidone is considered to play a more important role in QT prolongation than risperidone.