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.
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.
We reviewed 36 reported psychiatric patients who were treated with a combination of electroconvulsive therapy (ECT) and clozapine. The indication of the ECT-clozapine treatment was resistance to classical antipsychotic agents, clozapine, or ECT alone. Sixty-seven percent of the patients benefited from the combined treatment. In most of the patients, the combined treatment was safe and well tolerated. Adverse reactions occurred in 16.6% of the patients and included prolonged ECT-induced seizures (one case), supraventricular (one case) and sinus tachycardia, and blood pressure elevation. It seems that combined ECT-clozapine treatment is effective and safe. This strategy may be a therapeutic option in treatment-resistant patients.
Several recent studies, albeit limited in sample number, design and generalizability, have suggested that augmentation of atypical antipsychotic medication (such as clozapine and olanzapine) with sulpiride, a substituted benzamide antipsychotic medication, may play a role in the management of treatment-resistant psychotic conditions. The objective of this study was to investigate any change in clinical symptomatology or side-effect profile in treatment-resistant schizophrenia patients receiving sulpiride in addition to olanzapine. Seventeen patients with treatment-resistant chronic schizophrenia, who were receiving olanzapine monotherapy for at least 6 months before study commencement, were randomized in a 1:1 fashion to receive either adjunctive treatment with sulpiride (study group) or to continue their pre-study treatment with olanzapine with no medication augmentation (control group), each for a period of 8 weeks. Changes in measures of positive and negative symptoms, anxiety, depression and extrapyramidal symptoms were assessed at baseline and at 8 weeks. Study observations indicated no significant differences in the changes in positive or negative symptomatology between patients receiving a combined regimen of olanzapine with sulpiride (600 mg/ day) augmentation and controls. However, a significantly greater improvement of depressive symptomatology (P < 0.05; as assessed by the Hamilton Scale for Depression) was noted in the sulpiride augmentation group. These data indicate improvement in depressive symptomatology with sulpiride augmentation of olanzapine in treatment-resistant chronic schizophrenia patients.
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