A. Weizman

A Highly Significant Association between a COMT Haplotype and Schizophrenia

Several lines of evidence have placed the catechol-O-methyltransferase (COMT) gene in the limelight as a candidate gene for schizophrenia. One of these is its biochemical function in metabolism of catecholamine neurotransmitters; another is the microdeletion, on chromosome 22q11, that includes the COMT gene and causes velocardiofacial syndrome, a syndrome associated with a high rate of psychosis, particularly schizophrenia. The interest in the COMT gene as a candidate risk factor for schizophrenia has led to numerous linkage and association analyses. These, however, have failed to produce any conclusive result. Here we report an efficient approach to gene discovery. The approach consists of (i) a large sample size-to our knowledge, the present study is the largest case-control study performed to date in schizophrenia; (ii) the use of Ashkenazi Jews, a well defined homogeneous population; and (iii) a stepwise procedure in which several single nucleotide polymorphisms (SNPs) are scanned in DNA pools, followed by individual genotyping and haplotype analysis of the relevant SNPs. We found a highly significant association between schizophrenia and a COMT haplotype (P=9.5x10-8). The approach presented can be widely implemented for the genetic dissection of other common diseases.

COMT: A common susceptibility gene in bipolar disorder and schizophrenia

A variety of psychiatric illnesses, including schizophrenia and bipolar disorder, have been reported in patients with microdeletion on chromosome 22q11—a region which includes the catechol‐O‐methyltransferase (COMT) gene. The variety of psychiatric manifestations in patients with the 22q11 microdeletion and the role of COMT in the degradation of catecholamine neurotransmitters may thus suggest a general involvement of the COMT gene in psychiatric diseases. We have previously reported on a significant association between a COMT haplotype and schizophrenia. In this study, we attempt to test for association between bipolar disorder and the polymorphisms implicated in schizophrenia. The association between COMT and bipolar disorder was tested by examining the allele and haplotype found to be associated with schizophrenia. A significant association between bipolar disorder and COMT polymorphisms was found. The estimated relative risk is greater in women, a result consistent with our previous findings in schizophrenia. We suggest that polymorphisms in the COMT gene may influence susceptibility to both diseases—and probably also a wider range of behavioral traits.

Elevated circulatory level of GABA(A)--antagonistic neurosteroids in patients with combat-related post-traumatic stress disorder.

BACKGROUND Post-traumatic stress disorder (PTSD) is a multisystem neurobiological disorder with chronic alterations in various neurochemical systems. Levels of the GABA(A)--antagonistic neurosteroids plasma dehydroepiandrosterone (DHEA) and its sulphate derivate, dehydroepiandrosterone sulphate (DHEAS) may be relevant to depressive and anxiety disorders, including PTSD. METHODS We assessed the circulatory levels of morning plasma DHEA and DHEAS in 21 male outpatients with untreated chronic combat-related PTSD (CR-PTSD), and 18 healthy control male subjects. RESULTS Compared with the control subjects, the PTSD patients showed significantly higher plasma DHEA and DHEAS levels. CONCLUSIONS Chronic CR-PTSD may be associated with increased circulatory level of neuroactive steroids with inhibitory activity at the GABA(A) receptors. Neurosteroid-induced decreased GABAergic tone may be relevant to the symptomatology and pathophysiology of chronic PTSD, as well as to the frequent co-morbidity of PTSD with depression and anxiety disorders.

Circulatory levels of catecholamines, serotonin and lipids in attention deficit hyperactivity disorder.

Attention deficit hyperactivity disorder (ADHD) may be associated with a dysregulation of the catecholaminergic and serotonergic systems. Furthermore, ADHD is frequently complicated by aggressive impulsive behaviour, which is suggested to be related to low serum cholesterol levels. We examined the relationship between blood serotonin, norepinephrine, dopa and lipid levels and the degree of hyperactivity, impulsiveness, lack of concentration, and aggressiveness in boys with ADHD of low and high severity as determined by a specially designed formulated scale based on the DSM‐IV criteria for ADHD. No differences were noted between the groups in any of the peripheral biological parameters except blood serotonin, for which a tendency (P =0.08) towards lower levels was observed in the children with more severe disorder. We conclude that children with severe ADHD may have a different serotonin turnover compared to children with mild ADHD. These results may have implications for our understanding of the pathogenesis of ADHD, at least the more severe type.

Haloperidol-induced neurotoxicity--possible implications for tardive dyskinesia.

Summary. Tardive dyskinesia (TD) is one of the major side effects of long – term neuroleptic treatment. The pathophysiology of this disabling and commonly irreversible movement disorder is still obscure. The traditional concept of supersensitivity of striatal dopamine receptors as the mechanism involved in the development of TD is not satisfying, and current studies have focused on the role of neuroleptic – induced neuronal toxicity in the development of TD. We performed a series of experiments to gain a better understanding on the mechanisms involved in induction of TD. We have evaluated the direct neurotoxic effect of haloperidol (HP), a widely – used neuroleptic drug, and its three metabolites, in mouse neuronal cultures and in PC-12 cells.We found that the features of HP-induced cell death were apoptotic rather than necrotic, as indicated by different DNA-staining methods and specific caspases inhibitors. Moreover, cotreatment with antioxidants such as vitamin E and N-acetylcysteine (NAC) significantly protected the cultures. Further studies on the mechanisms underlying HP-induced toxicity may lead to the development of new neuroprotective therapeutic strategies.

Oral health and treatment needs of institutionalized chronic psychiatric patients in Israel

The aim of the study was to examine the oral health and treatment needs of chronically hospitalized psychiatric patients in Israel. Ten percent of the patients hospitalized for more than 2 years in the 18 psychiatric institutions in Israel were selected at random. The dental status (DMF-T index) was calculated, demographic and medical data were retrieved from the files. Of the 431 patients examined (250 men, 181 women, average age 54 years) 312 patients had only partial natural dentition. The average DMF-T score was 26.74 (out of 32), one of the highest in the literature. The caries component accounted for 2.3% of the DMF-T, the missing teeth component 72% and the restored teeth component 5%. There was an adverse correlation between age and caries and between duration of hospitalization and number of teeth. The average number of carious and missing teeth was higher than in the healthy population. No all-edentulous patients had dentures. These findings confirm the urgent need for an intervention program to improve dental health care in high-risk, difficult-to-treat, psychiatric chronic inpatients.

Fluvoxamine treatment of obsessive-compulsive symptoms in schizophrenic patients: an add-on open study.

Obsessive-Compulsive (OC) symptoms are observed in a substantial proportion of schizophrenic patients and pose a significant therapeutic challenge. Based on findings of the benefit of the anti-obsessive agent clomipramine, we designed an open-label study to examine the effect of adding the serotonin-selective reuptake inhibitor (SSRI) fluvoxamine to the ongoing antipsychotic regimen of schizo-obsessive patients. The study population consisted of ten neuroleptic-stabilized chronic schizophrenic patients with OC symptoms. Fluvoxamine (up to 150 mg/day) was added to the ongoing antipsychotic treatment, which remained unchanged for the entire 12-week trial period. The patients were evaluated before the trial and at weeks 1, 2, 4, 6, 8 and 12 (end point) with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Schedule for Assessment of Positive Symptoms and the Schedule for Assessment of Negative Symptoms. The results showed a significant improvement in obsessions (P < 0.02) (but not compulsions) and both positive (P < 0.01) and negative (P < 0.05) schizophrenic symptoms. By the end of the trial, three patients showed a more than 50% reduction in the Y-BOCS score, with complete amelioration of the OC symptoms in one of them. Three patients were dropped from the study during the first 4 weeks, two because of aggressiveness and one because of psychotic exacerbation. No exacerbation or new onset of extrapyramidal side-effects (EPS), as measured by the Barnes Akathisia Scale (BARS) and the Simpson-Angus Scale (SAS), was noted during the course of the trial and there were no other significant clinical side-effects of fluvoxamine addition. We conclude that fluvoxamine may be an effective adjunctive agent in some schizo-obsessive patients.

Lateral preference in post-traumatic stress disorder

BACKGROUND We assessed lateral preference in 80 male patients with combat-related post-traumatic stress disorder (PTSD) and in 100 healthy age-matched male controls. METHODS Hand, foot, eye and ear preferences were examined, using the Edinburgh Handedness Inventory-Modified and the Coren Inventory of Lateral Preference. RESULTS Mixed lateral preference was noted in significantly more PTSD patients than controls (65 v. 43%, P < 0.005). CONCLUSIONS These results indicate a possible hemispheric imbalance (less lateralization) in PTSD patients, with the right hemisphere playing a more active role in perceptual and cognitive processing and in the regulation of biological responses in these patients. This imbalance may be relevant to the pathophysiology of PTSD.

Trihexyphenidyl treatment of clozapine-induced hypersalivation.

The objective of this study was to investigate the efficacy of the anticholinergic agent trihexyphenidyl in the treatment of cluzapine-induced hypersalivation. Fourteen chronic schizophrenic patients who exhibited nocturnal hypersalivation during clozapine treatment were coadministered trihexvphenidyl (5–15 mg/day, at bedtime) for 15 days. Salivation was assessed by a single-item 5-point scale. A reduction of 44% in the reported nocturnal hypersalivation was observed after trihexyhenidyl treatment. These results indicate that at least some; chronic schizophrenic patients with clozapine-induced nocturnal hypersalivation may benefit from anticholinergic treatment.

A complete genetic association scan of the 22q11 deletion region and functional evidence reveal an association between DGCR2 and schizophrenia

Several lines of evidence have established the presence of an association between a 3-Mb deletion in chromosome 22q11 and schizophrenia. In this paper we present a complete high-density SNP scan of this segment using DNA pools, and demonstrate significant association between two distinct regions and schizophrenia in an Ashkenazi Jewish population. One of these regions contains the previously identified COMT gene. The pattern of association and linkage disequilibrium (LD) in the second region suggest that DGCR2, which encodes a putative adhesion receptor protein, is the susceptibility gene. We confirmed the association between DGCR2 and schizophrenia through individual genotyping of 1,400 subjects. In a gene expression analysis the risk allele of a coding SNP associated with schizophrenia was found to be associated with a reduced expression of DGCR2. Interestingly, the expression of DGCR2 was also found to be elevated in the dorsolateral prefrontal cortex of schizophrenic patients relative to matched controls. This increase is likely to be explained by exposure to antipsychotic drugs. To test that hypothesis, we looked at rats exposed to antipsychotic medication and found significantly elevated levels of DGCR2 transcripts. The genetic and functional evidences here reported suggest a possible role of the DGCR2 gene in the pathology of schizophrenia and also in the therapeutic effects of antipsychotic drugs.