Schizophrenia

The Candidate Schizophrenia Risk Gene Tmem108 Regulates Glucose Metabolism Homeostasis

BACKGROUND

Schizophrenia (SCZ) is a severe psychiatric disease affected by genetic factors and environmental contributors, and premorbid abnormality of glucose metabolism is one of the SCZ characteristics supposed to contribute to the disease's pathological process. Transmembrane protein 108 (Tmem108) is a susceptible gene associated with multiple psychiatric diseases, including SCZ. Moreover, Tmem108 mutant mice exhibit SCZ-like behaviors in the measurement of sensorimotor gating. However, it is unknown whether Tmem108 regulates glucose metabolism homeostasis while it involves SCZ pathophysiological process.

RESULTS

In this research, we found that Tmem108 mutant mice exhibited glucose intolerance, insulin resistance, and disturbed metabolic homeostasis. Food and oxygen consumption decreased, and urine production increased, accompanied by weak fatigue resistance in the mutant mice. Simultaneously, the glucose metabolic pathway was enhanced, and lipid metabolism decreased in the mutant mice, consistent with the elevated respiratory exchange ratio (RER). Furthermore, metformin attenuated plasma glucose levels and improved sensorimotor gating in Tmem108 mutant mice.

CONCLUSIONS

Hyperglycemia occurs more often in SCZ patients than in control, implying that these two diseases share common biological mechanisms, here we demonstrate that the Tmem108 mutant may represent such a comorbid mechanism.

Genetic variation throughout the folate metabolic pathway influences negative symptom severity in schizophrenia

Low serum folate levels previously have been associated with negative symptom risk in schizophrenia, as has the hypofunctional 677C>T variant of the MTHFR gene. This study examined whether other missense polymorphisms in folate-regulating enzymes, in concert with MTHFR, influence negative symptoms in schizophrenia, and whether total risk allele load interacts with serum folate status to further stratify negative symptom risk. Medicated outpatients with schizophrenia (n = 219), all of European origin and some included in a previous report, were rated with the Positive and Negative Syndrome Scale. A subset of 82 patients also underwent nonfasting serum folate testing. Patients were genotyped for the MTHFR 677C>T (rs1801133), MTHFR 1298A>C (rs1801131), MTR 2756A>G (rs1805087), MTRR 203A>G (rs1801394), FOLH1 484T>C (rs202676), RFC 80A>G (rs1051266), and COMT 675G>A (rs4680) polymorphisms. All genotypes were entered into a linear regression model to determine significant predictors of negative symptoms, and risk scores were calculated based on total risk allele dose. Four variants, MTHFR 677T, MTR 2756A, FOLH1 484C, and COMT 675A, emerged as significant independent predictors of negative symptom severity, accounting for significantly greater variance in negative symptoms than MTHFR 677C>T alone. Total allele dose across the 4 variants predicted negative symptom severity only among patients with low folate levels. These findings indicate that multiple genetic variants within the folate metabolic pathway contribute to negative symptoms of schizophrenia. A relationship between folate level and negative symptom severity among patients with greater genetic vulnerability is biologically plausible and suggests the utility of folate supplementation in these patients.

Diverse roles of neurotensin agonists in the central nervous system

Neurotensin (NT) is a tridecapeptide that is found in the central nervous system (CNS) and the gastrointestinal tract. NT behaves as a neurotransmitter in the brain and as a hormone in the gut. Additionally, NT acts as a neuromodulator to several neurotransmitter systems including dopaminergic, sertonergic, GABAergic, glutamatergic, and cholinergic systems. Due to its association with such a wide variety of neurotransmitters, NT has been implicated in the pathophysiology of several CNS disorders such as schizophrenia, drug abuse, Parkinson's disease (PD), pain, central control of blood pressure, eating disorders, as well as, cancer and inflammation. The present review will focus on the role that NT and its analogs play in schizophrenia, endocrine function, pain, psychostimulant abuse, and PD.

14q13.1-21.1 deletion encompassing the HPE8 locus in an adolescent with intellectual disability and bilateral microphthalmia, but without holoprosencephaly

Interstitial deletions involving 14q13.1q21.1 are rare. In the literature at least 10 cases involving this region have been described and all patients showed a phenotype within the holoprosencephaly (HPE) spectrum. Previous studies suggested the HPE8 region as a candidate locus for HPE at 14q13. We report an adolescent with a 14q13.1q21.1 deletion encompassing the HPE8 region associated with intellectual disability (ID), bilateral microphthalmia, and coloboma, without cerebral anomalies typical of HPE. Except for ocular defects (i.e., microphthalmia, coloboma) consistent with HPE-type anomalies, the minor facial dysmorphia was not suggestive for HPE and the absence of cerebral anomalies should rule out this diagnosis. The deletion of the potential HPE candidate genes NPAS3, EAPP, SNX6, and TULIP1, raises doubts about their pathologic role in determining HPE. It is likely that deletions of HPE genes are not sufficient to cause HPE, and that multiple genetic, chromosomal, and environmental factors interact to determine the variable clinical expression of HPE. This is the first case of a 14q deletion encompassing the HPE8 locus with the only features consistent with HPE-type anomalies affecting the ocular system (i.e., microphthalmia, coloboma), and without cerebral anomalies specific for HPE. The inclusion of potential HPE candidate genes in the deletion raises the question whether this patient is affected by a less severe form of HPE (HPE microform), or whether he has a new ID/MCA deletion syndrome.

Appendectomy for appendicitis in patients with schizophrenia

BACKGROUND

Anecdotal evidence suggests that schizophrenia patients who require surgery have a high rate of adverse outcomes. We searched the Department of Veterans Affairs national datasets to determine the clinical course of schizophrenia patients with appendicitis who underwent appendectomy.

METHODS

The Patient Treatment File (the nationwide inpatient database for the Department of Veterans Affairs) and the Beneficiary Identification and Records Location System were searched to identify all patients with International Classification of Diseases, Ninth Revision, Clinical Modification diagnostic codes for schizophrenia or schizoaffective disorder diagnosed with appendicitis during fiscal years 1995 to 1999. Computer-based information was supplemented with chart-based data. We sought data on six common preoperative risk factors and 25 specific adverse outcomes, including death.

RESULTS

There were 55 patients identified. The mean age was 49, and 96% were men. The median time from symptom onset to diagnosis of appendicitis was 3 days. A history of substance abuse was obtained in 16 (29%). Disruptive behavior was documented in 16 (29%). Restraints were used in 9 (9%). The appendix was perforated in 36 (66%) and gangrenous in 9 (16%). Thirty-one (56%) had > or = 1 complication; there were 2 in-hospital deaths (4%).

CONCLUSIONS

This is the first report on this topic in the medical literature. Appendicitis is typically diagnosed late in schizophrenic patients. Adverse patient behaviors are frequent. The complication and death rates are high.

Wie viel allgemeinmedizinische Kompetenz ben�tigen Psychiater?

Due to manifold interactions between physical and mental health, there exist close interactions between psychiatric care and that from other medical fields. In this regard, points of general medical practice are discussed as they relate to psychiatric care. The frequency of somatic comorbidities in patients with mental disorders and a rising proportion of elderly patients are strong arguments for inclusion of general medical elements in psychiatric and psychotherapeutic training.

Comparison of Classical and Clozapine Treatment on Schizophrenia Using Positive and Negative Syndrome Scale of Schizophrenia (PANSS) and SPECT Imaging

Many neuroimaging studies of schizophrenia have shown abnormalities in the frontal cortex, limbic system, basal ganglia, temporal and parietal lobes. These findings are not specific or consistent enough to build up a coherent theory of the origin of the brain abnormality in schizophrenia. This paper describes a state-of-the-art approach of SPECT to correlate neuropsychological evaluation. PANSS scores and different brain focal abnormalities of two groups of patients receiving Clozapine and classical antipsychotic treatments were observed. A total of 20 drug-free patients, actively psychotic schizophrenic, were selected according to the DSM-IV criteria. Pre-Post-treatment was designed using PANSS and 99mTc- ECD-SPECT to assess regional Cerebral Blood Flow (rCBF). The results showed that after treatment, differences in PANSS scores were significant in both groups, with superior scores resulting from the Clozapine therapy. Results were supported by SPECT, which showed a greater improvement in the Clozapine group. Both positive and negative symptoms were improved with Clozapine as well. Before treatment, hypofrontality was the most common (85%) finding, whereas after treatment hypofrontality was mostly cleared. However, in some areas like temporal and caudate, hyperfrontality was induced. Negative symptoms showed linkage to hypofrontality in both groups before and after treatment, and both positive and negative symptoms were improved more with Clozapine therapy than with classical treatment.

Acute effects of gabapentin on laboratory measures of aggressive and escape responses of adult parolees with and without a history of conduct disorder

RATIONALE

The possible role of GABA in human aggression was evaluated by administering gabapentin to subjects with and without a history of conduct disorder and comparing the effects on laboratory measures of aggression and escape.

METHODS

Eighteen male and two female subjects with a history of criminal behavior participated in experimental sessions, which measured aggressive and escape responses. Ten subjects had a history of childhood conduct disorder (CD+) and ten subjects with no history (non-CD controls). Aggression was measured using the Point Subtraction Aggression Paradigm (PSAP), which provided subjects aggressive, escape and monetary reinforced response options.

RESULTS

Acute doses (200, 400 and 800 mg) of gabapentin had similar effects on aggressive responses among CD+ subjects compared to non-CD control subjects. Aggressive responses of CD+ and non-CD control subjects increased at lower gabapentin doses, and decreased at the highest 800 mg gabapentin dose. Gabapentin increased escape responses for both CD+ and non-CD controls CD- subjects at the lowest dose, but then produced dose-related decreases at the two higher doses in both groups. No changes in monetary reinforced responses were observed, indicative of no CNS stimulation or sedation.

CONCLUSIONS

Gabapentin produced similar bitonic effects upon aggressive and escape responses in subjects with and without a history of childhood conduct disorder. This is in marked contrast to prior differential effects of baclofen on aggressive responses between CD+ and non-CD control subjects in a previous study.

Pharmacokinetics and QT interval pharmacodynamics of oral haloperidol in poor and extensive metabolizers of CYP2D6

We studied the pharmacokinetics and QT interval pharmacodynamics of a single 10 mg dose of oral haloperidol in a randomized, double-blind, placebo-controlled, crossover trial of healthy poor (PMs) and extensive (EMs) metabolizers of CYP2D6. There was a statistically significant greater mean QT(c) on haloperidol (421.6+/-20.1 ms) than on placebo (408.4+/-18.5 ms, P=0.0053) occurring 10 h post haloperidol/placebo administration. Men and women had similar ranges of QT(c) changes from placebo. Despite a statistically significant greater mean elimination half-life (19.1+/-3.6 vs 12.9+/-4.0 h, P=0.04) and lower mean apparent oral clearance (12.8+/-4.1 vs 27.0+/-11.3 ml/min/kg, P=0.02) of haloperidol in CYP2D6 PMs than in EMs, this exposure change did not translate into marked QT(c) changes from baseline that could be considered clinically important. Although the magnitude of the mean QT(c) prolongation on haloperidol relative to placebo is relatively small, it may assume significance in the presence of other risk factors for QT prolongation.

Disruption of the neuronal PAS3 gene in a family affected with schizophrenia

Schizophrenia and its subtypes are part of a complex brain disorder with multiple postulated aetiologies. There is evidence that this common disease is genetically heterogeneous, with many loci involved. In this report, we describe a mother and daughter affected with schizophrenia, who are carriers of a t(9;14)(q34;q13) chromosome. By mapping on flow sorted aberrant chromosomes isolated from lymphoblast cell lines, both subjects were found to have a translocation breakpoint junction between the markers D14S730 and D14S70, a 683 kb interval on chromosome 14q13. This interval was found to contain the neuronal PAS3 gene (NPAS3), by annotating the genomic sequence for ESTs and performing RACE and cDNA library screenings. The NPAS3 gene was characterised with respect to the genomic structure, human expression profile, and protein cellular localisation to gain insight into gene function. The translocation breakpoint junction lies within the third intron of NPAS3, resulting in the disruption of the coding potential. The fact that the bHLH and PAS domains are disrupted from the remaining parts of the encoded protein suggests that the DNA binding and dimerisation functions of this protein are destroyed. The daughter (proband), who is more severely affected, has an additional microdeletion in the second intron of NPAS3. On chromosome 9q34, the translocation breakpoint junction was defined between D9S752 and D9S972 and no genes were found to be disrupted. We propose that haploinsufficiency of NPAS3 contributes to the cause of mental illness in this family.

Clinical experience with the management of schizophrenia in the general hospital

On the basis of experience with 74 psychiatric consultations involving patients with schizophrenia admitted to a general hospital medical or surgical ward over a 17-month period (3% of the psychiatric consultations during that period), the authors identified 10 types of problems leading to requests for consultation. The authors used these categories to organize recommendations for management of patients with schizophrenia in the general medical hospital. In addition to conducting conventional consultations, the consultation psychiatrist in such cases often has a role in educating hospital staff about schizophrenia and in serving as a physician for the mentally ill.

Role of the psychiatrist in the care of patients with hepatitis C and HIV/AIDS

Hepatitis C and HIV/AIDS are among the most significant infectious diseases of our time. Psychiatric patients are often part of the higher risk population to contract these diseases, and patients who have contracted these diseases experience a wide variety of psychiatric problems associated with the underlying infection and with its treatment. The authors provide an overview of these infectious diseases and then describe the varying roles psychiatrists have in caring for these patients in the various settings of their work. The complexity of these patients presents a unique challenge to, and opportunity for, psychiatrists to integrate and coordinate their interventions with those of other medical providers and thereby enhance the patient's cooperation with all aspects of care.

Genetics and etiopathophysiology of schizophrenia

Schizophrenia is one of the most common, devastating, and least understood neuropsychiatric illnesses present in the human population. Despite decades of research involving neurochemical, neuroanatomical, neuropathologic, neurodevelopmental, neuropsychological, and genetic approaches, no clear etiopathophysiology has been elucidated. Among the most robust findings, however, is the contribution of genetics to disease development. Statistical models suggest that susceptibility to the disorder is governed by the effects of multiple genes, coupled with environmental and stochastic factors. This review briefly summarizes recent etiopathologic findings and hypotheses, with special attention to genetics.

The psychopathology, medical management and dental implications of schizophrenia

BACKGROUND

Schizophrenia is a psychiatric illness characterized by thought disturbances, bizarre behaviors and cognitive impairments that may diminish a person's abilities in the areas of social relations, school or work and self-care. The onset of the disorder typically occurs between the late teens and mid-30s. Advanced dental disease is seen frequently in patients with schizophrenia for several reasons: the disease impairs these patients' ability to plan and perform oral hygiene procedures; some of the antipsychotic medications they take have adverse orofacial effects such as xerostomia; and these patients sometimes have limited access to treatment because of a paucity of financial resources and adequate number of dentists comfortable in providing care. The recent introduction of more effective medications has permitted the majority of patients to receive their psychiatric care from community-based providers rather than in the hospital. Consequently, dentists in the private sector also are being called on more frequently to care for these people.

CONCLUSIONS

Dentists cognizant of the signs and symptoms of schizophrenia are likely to feel more secure in treating patients with schizophrenia and more confident when obtaining consultative advice from the patients' psychiatrists. Dentists usually can provide a full range of services to such patients, can enhance these patients' self-esteem and can contribute to the psychotherapeutic aspect of management.

CLINICAL IMPLICATIONS

To effectively provide treatment to patients with schizophrenia, dentists must be familiar with the disease process so that they can communicate effectively with the patient, the treating psychiatrist and family members who serve as caregivers. In addition, dental treatment may need to be modified because of the patient's impaired ability to think logically, the local and systemic effects of psychiatric medications, and adverse interactions between these drugs and medications used in dentistry.