In the last decade, long-acting injectable antipsychotics has been widely used in schizophrenia. ... more In the last decade, long-acting injectable antipsychotics has been widely used in schizophrenia. Aripiprazole long-acting once-monthly (AOM) is the only long-acting dopamine partial agonist antipsychotic approved for schizophrenia; however, a literature search revealed no guidance on safely switching from oral and long-acting injectable antipsychotics to AOM. This study aimed to develop recommendations of AOM use based on existing data and expert consensus. A committee of 30 experts in psychopharmacology from major hospitals across Taiwan was invited. A modified Delphi method was conducted, consisting of two rounds of questionnaires, literature review, three rounds of face-to-face discussion meeting, and two rounds of anonymous voting. The consensus recommendations were developed based on existing data, clinical experiences, and consensus opinions, with 80% agreement among panel members required for final adoption. The panel developed nine consensus statements of switching to AOM fo...
Both prepulse inhibition (PPI) and prepulse facilitation (PPF) deficits have been reported in sch... more Both prepulse inhibition (PPI) and prepulse facilitation (PPF) deficits have been reported in schizophrenia patients, but the use of different experimental parameters across laboratories makes direct comparisons of results difficult. We assessed the effects of different parameters on PPI and PPF in normal subjects. Eyeblink startle was measured in 14 healthy male subjects, using 115 dB[A] white noise startle pulses and 86 dB[A] prepulses. Analyses compared the effects of: 1) background noise level (ambient 54 vs. 70 dB[A]) on PPI and PPF, 2) prepulse duration (discrete 20 msec vs. continuous) on PPF, 3) prepulse frequency (1000 Hz vs. white noise) on PPI and PPF, and 4) prepulse interval (2000 vs. 4500 msec) on PPF. Compared to an experimentally delivered 70 dB[A] background, ambient 54 dB[A] background led to significantly more PPI (with discrete white noise prepulses), and more PPF (with continuous prepulses). Continuous and longer (4500 msec) prepulses induced more PPF than did discrete and shorter (2000 msec) prepulses. Paradigmatic differences appear likely to be responsible for divergent findings in studies of PPI and PPF in normal and schizophrenia subjects. The present study should guide investigators in the selection of parameters for assessing PPI and PPF in studies of normal subjects and schizophrenia patients. Attention to the 4 factors of 1) background noise, 2) prepulse duration, 3) frequency, and 4) interval will facilitate comparability of results across different laboratories, especially when using PPI/PPF in schizophrenia research as neural substrate probes, as biomarkers, and as endophenotypes.
Gamma band activity has been associated with many sensory and cognitive functions, and is importa... more Gamma band activity has been associated with many sensory and cognitive functions, and is important for cortico-cortical transmission and the integration of information across neural networks. The aims of the present study were to determine if schizophrenia patients have deficits in the generation and maintenance of coherent, synchronized oscillations in response to steady-state stimulation, and to examine the clinical and cognitive correlates of the electroencephalography (EEG) oscillatory dynamics. Schizophrenia patients (n = 100) and nonpsychiatric subjects (n = 80) underwent auditory steady-state event-related potential testing. Click trains varying in rate of stimulation (20, 30, and 40 Hz) were presented; EEG-evoked power and intertrial phase synchronization were obtained in response to each stimulation frequency. Subjects also underwent clinical and neurocognitive assessments. Patients had reductions in both evoked power and phase synchronization in response to 30- and 40-Hz stimulation but normal responsivity to 20-Hz stimulation. Maximal deficits were detected in response to 40-Hz stimulation. A modest association of reduced working memory performance and 40-Hz intertrial phase synchronization was present in schizophrenia patients (r = .32, p <.01). Schizophrenia patients have frequency-specific deficits in the generation and maintenance of coherent gamma-range oscillations, reflecting a fundamental degradation of basic integrated neural network activity.
Background Implicit learning was reported to be intact in schizophrenia using artificial grammar ... more Background Implicit learning was reported to be intact in schizophrenia using artificial grammar learning. However, emerging evidence indicates that artificial grammar learning is not a unitary process. The authors used dual coding stimuli and schizophrenia clinical symptom dimensions to re-evaluate the effect of schizophrenia on various components of artificial grammar learning. Methods Letter string and color pattern artificial grammar learning performances were compared between 63 schizophrenic patients and 27 comparison subjects. Four symptom dimensions derived from a Chinese Positive and Negative Symptom Scale ratings were correlated with patients' artificial grammar implicit learning performances along the two stimulus dimensions. Patients' explicit memory performances were assessed by verbal paired associates and visual reproduction subtests of the Wechsler Memory Scales Revised Version to provide a contrast to their implicit memory function. Results Schizophrenia severely hindered color pattern artificial grammar learning while the disease affected lexical string artificial grammar learning to a lesser degree after correcting the influences from age, education and the performance of explicit memory function of both verbal and visual modalities. Both learning performances correlated significantly with the severity of patients' schizophrenic clinical symptom dimensions that reflect poor abstract thinking, disorganized thinking, and stereotyped thinking. Conclusion The results of this study suggested that schizophrenia affects various mechanisms of artificial grammar learning differently. Implicit learning, knowledge acquisition in the absence of conscious awareness, is not entirely intact in patients with schizophrenia. Schizophrenia affects implicit learning through an impairment of the ability of making abstractions from rules and at least in part decreasing the capacity for perceptual learning.
A genome scan of Taiwanese schizophrenia families suggested linkage to chromosome 10q22.3. We aim... more A genome scan of Taiwanese schizophrenia families suggested linkage to chromosome 10q22.3. We aimed to find the candidate genes in this region. A total of 476 schizophrenia families were included. Hierarchical clustering method was used for clustering families to homogeneous subgroups according to their performances of sustained attention and executive function. Association analysis was performed using family-based association testing and TRANSMIT. Candidate associated regions were identified using the longest significance run method. The relative messenger RNA expression level was determined using real-time reverse transcriptase polymerase chain reaction. First, we genotyped 18 microsatellite markers between D10S1432 and D10S1239. The maximum nonparametric linkage score was 2.79 on D10S195. Through family clustering, we found the maximum nonparametric linkage score was 3.70 on D10S195 in the family cluster with deficits in attention and executive function. Second, we genotyped 79 single nucleotide polymorphisms between D10S1432 and D10S580 in 90 attention deficit and execution deficit families. Association analysis indicated significant transmission distortion for nine single nucleotide polymorphisms. Using the longest significance run method, we identified a 427-kilobase region as a significant candidate region, which encompasses nine genes. Third, we studied messenger RNA expression of these nine genes in Epstein-Barr virus-transformed lymphoblastic cells. In schizophrenic patients, there was significantly lower expression of ANXA7, PPP3CB, and DNAJC9 and significantly higher expression of ZMYND17. ANXA7, PPP3CB, DNAJC9, and ZMYND17 genes are potential candidate genes for schizophrenia, especially in patients with deficits in sustained attention and executive function. The responsible functional variants remained to be clarified.
Existing studies have found the relationship between handedness and schizotypy to be inconsistent... more Existing studies have found the relationship between handedness and schizotypy to be inconsistent, and had limited generalisability since only highly homogeneous groups have been investigated. This study aimed to examine the relation between handedness and the four schizotypal factors identified from a previous confirmatory factor analysis in a population of high familial loading for schizophrenia. Study participants consisted of non-psychotic first-degree relatives (850 parents and 334 siblings) of sib-pairs who were co-affected with schizophrenia. All participants were interviewed with the Diagnostic Interview for Genetic Studies, which contains a section of the modified Structured Interview for Schizotypy, and the Annett handedness questionnaire. Both categorical and continuous indicators for handedness were examined. Non-right-handed siblings of schizophrenia patients displayed more positive schizotypal features than their right-handed counterparts when the two-way Annett's handedness classification was adopted. No association was found when handedness was treated as continuous. The relationship between handedness and schizotypy was insignificant for parents probably due to the strong social pressure against left-handedness. We concluded that categorical non-right-handedness was associated with positive schizotypy in non-psychotic siblings of schizophrenia patients. The results indicate that an atypical cerebral lateralisation underlying non-right-handedness may be also a contributing factor to positive schizotypy.
To describe the outcomes of subjects with suspected pre-psychotic state in Taiwan. A prospective ... more To describe the outcomes of subjects with suspected pre-psychotic state in Taiwan. A prospective clinical observation was performed on subjects recruited by referrals from a community-based population. Three pre-psychotic risk groups were established by means of clinical interviews: an ultra-high risk group (UHR; 59 subjects), an intermediate-risk group (IRG; 46 subjects), and a marginal-risk group (MRG; 48 subjects). Also recruited were 60 subjects with first-episode psychosis (FEP) and 144 normal controls (NC group). All subjects were aged 16 to 32 years. Of the 59 UHR subjects, 21 (35.6%) converted to FEP, including 15 with schizophrenia (6 had relatively brief positive yet persistent prominent negative symptoms), 2 with schizophreniform disorder, 1 with schizoaffective disorder, 2 with brief psychotic disorder, and 1 with bipolar disorder. The cumulative±SE rate of conversion to psychosis was 21.7%±5.4% at 6 months, 28.2%±6.2% at 12 months, 30.4%±6.4% at 18 months, and 33.3%±6.8% at 24 months. The UHR subjects who converted had a higher rate of initial antipsychotic use than those who did not convert. Only half of the IRG and two-thirds of the MRG subjects received follow-up, and none of them developed FEP. Our results lent support to both sides of the current debate regarding establishing a new diagnostic category of "psychosis risk syndrome." The divergent trajectories of the UHR subjects deserve more clinical attention, especially with regard to the use of antipsychotics and the presence of a group with prominent negative symptoms.
In the last decade, long-acting injectable antipsychotics has been widely used in schizophrenia. ... more In the last decade, long-acting injectable antipsychotics has been widely used in schizophrenia. Aripiprazole long-acting once-monthly (AOM) is the only long-acting dopamine partial agonist antipsychotic approved for schizophrenia; however, a literature search revealed no guidance on safely switching from oral and long-acting injectable antipsychotics to AOM. This study aimed to develop recommendations of AOM use based on existing data and expert consensus. A committee of 30 experts in psychopharmacology from major hospitals across Taiwan was invited. A modified Delphi method was conducted, consisting of two rounds of questionnaires, literature review, three rounds of face-to-face discussion meeting, and two rounds of anonymous voting. The consensus recommendations were developed based on existing data, clinical experiences, and consensus opinions, with 80% agreement among panel members required for final adoption. The panel developed nine consensus statements of switching to AOM fo...
Both prepulse inhibition (PPI) and prepulse facilitation (PPF) deficits have been reported in sch... more Both prepulse inhibition (PPI) and prepulse facilitation (PPF) deficits have been reported in schizophrenia patients, but the use of different experimental parameters across laboratories makes direct comparisons of results difficult. We assessed the effects of different parameters on PPI and PPF in normal subjects. Eyeblink startle was measured in 14 healthy male subjects, using 115 dB[A] white noise startle pulses and 86 dB[A] prepulses. Analyses compared the effects of: 1) background noise level (ambient 54 vs. 70 dB[A]) on PPI and PPF, 2) prepulse duration (discrete 20 msec vs. continuous) on PPF, 3) prepulse frequency (1000 Hz vs. white noise) on PPI and PPF, and 4) prepulse interval (2000 vs. 4500 msec) on PPF. Compared to an experimentally delivered 70 dB[A] background, ambient 54 dB[A] background led to significantly more PPI (with discrete white noise prepulses), and more PPF (with continuous prepulses). Continuous and longer (4500 msec) prepulses induced more PPF than did discrete and shorter (2000 msec) prepulses. Paradigmatic differences appear likely to be responsible for divergent findings in studies of PPI and PPF in normal and schizophrenia subjects. The present study should guide investigators in the selection of parameters for assessing PPI and PPF in studies of normal subjects and schizophrenia patients. Attention to the 4 factors of 1) background noise, 2) prepulse duration, 3) frequency, and 4) interval will facilitate comparability of results across different laboratories, especially when using PPI/PPF in schizophrenia research as neural substrate probes, as biomarkers, and as endophenotypes.
Gamma band activity has been associated with many sensory and cognitive functions, and is importa... more Gamma band activity has been associated with many sensory and cognitive functions, and is important for cortico-cortical transmission and the integration of information across neural networks. The aims of the present study were to determine if schizophrenia patients have deficits in the generation and maintenance of coherent, synchronized oscillations in response to steady-state stimulation, and to examine the clinical and cognitive correlates of the electroencephalography (EEG) oscillatory dynamics. Schizophrenia patients (n = 100) and nonpsychiatric subjects (n = 80) underwent auditory steady-state event-related potential testing. Click trains varying in rate of stimulation (20, 30, and 40 Hz) were presented; EEG-evoked power and intertrial phase synchronization were obtained in response to each stimulation frequency. Subjects also underwent clinical and neurocognitive assessments. Patients had reductions in both evoked power and phase synchronization in response to 30- and 40-Hz stimulation but normal responsivity to 20-Hz stimulation. Maximal deficits were detected in response to 40-Hz stimulation. A modest association of reduced working memory performance and 40-Hz intertrial phase synchronization was present in schizophrenia patients (r = .32, p <.01). Schizophrenia patients have frequency-specific deficits in the generation and maintenance of coherent gamma-range oscillations, reflecting a fundamental degradation of basic integrated neural network activity.
Background Implicit learning was reported to be intact in schizophrenia using artificial grammar ... more Background Implicit learning was reported to be intact in schizophrenia using artificial grammar learning. However, emerging evidence indicates that artificial grammar learning is not a unitary process. The authors used dual coding stimuli and schizophrenia clinical symptom dimensions to re-evaluate the effect of schizophrenia on various components of artificial grammar learning. Methods Letter string and color pattern artificial grammar learning performances were compared between 63 schizophrenic patients and 27 comparison subjects. Four symptom dimensions derived from a Chinese Positive and Negative Symptom Scale ratings were correlated with patients' artificial grammar implicit learning performances along the two stimulus dimensions. Patients' explicit memory performances were assessed by verbal paired associates and visual reproduction subtests of the Wechsler Memory Scales Revised Version to provide a contrast to their implicit memory function. Results Schizophrenia severely hindered color pattern artificial grammar learning while the disease affected lexical string artificial grammar learning to a lesser degree after correcting the influences from age, education and the performance of explicit memory function of both verbal and visual modalities. Both learning performances correlated significantly with the severity of patients' schizophrenic clinical symptom dimensions that reflect poor abstract thinking, disorganized thinking, and stereotyped thinking. Conclusion The results of this study suggested that schizophrenia affects various mechanisms of artificial grammar learning differently. Implicit learning, knowledge acquisition in the absence of conscious awareness, is not entirely intact in patients with schizophrenia. Schizophrenia affects implicit learning through an impairment of the ability of making abstractions from rules and at least in part decreasing the capacity for perceptual learning.
A genome scan of Taiwanese schizophrenia families suggested linkage to chromosome 10q22.3. We aim... more A genome scan of Taiwanese schizophrenia families suggested linkage to chromosome 10q22.3. We aimed to find the candidate genes in this region. A total of 476 schizophrenia families were included. Hierarchical clustering method was used for clustering families to homogeneous subgroups according to their performances of sustained attention and executive function. Association analysis was performed using family-based association testing and TRANSMIT. Candidate associated regions were identified using the longest significance run method. The relative messenger RNA expression level was determined using real-time reverse transcriptase polymerase chain reaction. First, we genotyped 18 microsatellite markers between D10S1432 and D10S1239. The maximum nonparametric linkage score was 2.79 on D10S195. Through family clustering, we found the maximum nonparametric linkage score was 3.70 on D10S195 in the family cluster with deficits in attention and executive function. Second, we genotyped 79 single nucleotide polymorphisms between D10S1432 and D10S580 in 90 attention deficit and execution deficit families. Association analysis indicated significant transmission distortion for nine single nucleotide polymorphisms. Using the longest significance run method, we identified a 427-kilobase region as a significant candidate region, which encompasses nine genes. Third, we studied messenger RNA expression of these nine genes in Epstein-Barr virus-transformed lymphoblastic cells. In schizophrenic patients, there was significantly lower expression of ANXA7, PPP3CB, and DNAJC9 and significantly higher expression of ZMYND17. ANXA7, PPP3CB, DNAJC9, and ZMYND17 genes are potential candidate genes for schizophrenia, especially in patients with deficits in sustained attention and executive function. The responsible functional variants remained to be clarified.
Existing studies have found the relationship between handedness and schizotypy to be inconsistent... more Existing studies have found the relationship between handedness and schizotypy to be inconsistent, and had limited generalisability since only highly homogeneous groups have been investigated. This study aimed to examine the relation between handedness and the four schizotypal factors identified from a previous confirmatory factor analysis in a population of high familial loading for schizophrenia. Study participants consisted of non-psychotic first-degree relatives (850 parents and 334 siblings) of sib-pairs who were co-affected with schizophrenia. All participants were interviewed with the Diagnostic Interview for Genetic Studies, which contains a section of the modified Structured Interview for Schizotypy, and the Annett handedness questionnaire. Both categorical and continuous indicators for handedness were examined. Non-right-handed siblings of schizophrenia patients displayed more positive schizotypal features than their right-handed counterparts when the two-way Annett's handedness classification was adopted. No association was found when handedness was treated as continuous. The relationship between handedness and schizotypy was insignificant for parents probably due to the strong social pressure against left-handedness. We concluded that categorical non-right-handedness was associated with positive schizotypy in non-psychotic siblings of schizophrenia patients. The results indicate that an atypical cerebral lateralisation underlying non-right-handedness may be also a contributing factor to positive schizotypy.
To describe the outcomes of subjects with suspected pre-psychotic state in Taiwan. A prospective ... more To describe the outcomes of subjects with suspected pre-psychotic state in Taiwan. A prospective clinical observation was performed on subjects recruited by referrals from a community-based population. Three pre-psychotic risk groups were established by means of clinical interviews: an ultra-high risk group (UHR; 59 subjects), an intermediate-risk group (IRG; 46 subjects), and a marginal-risk group (MRG; 48 subjects). Also recruited were 60 subjects with first-episode psychosis (FEP) and 144 normal controls (NC group). All subjects were aged 16 to 32 years. Of the 59 UHR subjects, 21 (35.6%) converted to FEP, including 15 with schizophrenia (6 had relatively brief positive yet persistent prominent negative symptoms), 2 with schizophreniform disorder, 1 with schizoaffective disorder, 2 with brief psychotic disorder, and 1 with bipolar disorder. The cumulative±SE rate of conversion to psychosis was 21.7%±5.4% at 6 months, 28.2%±6.2% at 12 months, 30.4%±6.4% at 18 months, and 33.3%±6.8% at 24 months. The UHR subjects who converted had a higher rate of initial antipsychotic use than those who did not convert. Only half of the IRG and two-thirds of the MRG subjects received follow-up, and none of them developed FEP. Our results lent support to both sides of the current debate regarding establishing a new diagnostic category of "psychosis risk syndrome." The divergent trajectories of the UHR subjects deserve more clinical attention, especially with regard to the use of antipsychotics and the presence of a group with prominent negative symptoms.
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Papers by Ming H. Hsieh