Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mood disorders and schizophrenia share a number of common properties, including: genetic susceptibility; differences in brain structure and drug based therapy. Some genetic loci may even confer susceptibility for bipolar mood disorder and schizophrenia, and some atypical antipsychotic drugs are used as mood stabilizers. As schizophrenia is associated with aberrant neurodevelopment, could this also be true for mood disorders? Such changes could arise pre- or post-natal, however the recent interest in neurogenesis in the adult brain has suggested involvement of these later processes in the origins of mood disorders. Interestingly, the common mood stabilizing drugs, lithium, valproic acid (VPA) and carbamazepine, are teratogens, affecting a number of aspects of animal development. Recent work has shown that lithium and VPA interfere with normal cell development, and all three drugs affect neuronal morphology. The molecular basis for mood stabilizer action in the treatment of mood is unknown, however these studies have suggested both targets and potential mechanisms. Lithium directly inhibits two evolutionarily conserved signal transduction pathways: the protein kinase Glycogen Synthase Kinase-3 (GSK-3) and inositol signaling. VPA can up-regulate gene expression through inhibition of histone deacetylase (HDAC) and indirectly reduce GSK-3 activity. VPA effects are not conserved between cell types, and carbamazepine has no effect on the GSK-3 pathway. All three mood stabilizers suppress inositol signaling, results further supported by studies on the enzyme prolyl oligopeptidase (PO) and the sodium myo-inositol transporter (SMIT). Despite these intriguing observations, it remains unclear whether GSK-3, inositol signaling or both underlie the origins of bipolar disorder.
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PMID:Neurodevelopment and mood stabilizers. 1294

The suicide-related mortality among patients with affective disorders is approximately 30 times higher, and overall mortality 2 to 3 times higher, than suicide-related mortality in the general population. Lithium has demonstrated possibly specific antisuicidal effects apart from its prophylactic efficacy: it significantly reduces the high excess mortality of patients with affective disorders. To date, suicide-prevention effects have not been shown for antidepressant or anticonvulsant long-term treatment. Clozapine appears to reduce the suicide rate in schizophrenia patients. Against this background, guidelines and algorithms for selecting an appropriate prophylactic strategy for affective disorders should consider the presence of suicidality in patient history. Appropriate lithium prophylaxis prevents approximately 250 suicides yearly in Germany, although lithium salts are infrequently prescribed within the National Health Scheme (specifically, to 0.06% of the population). Rational treatment strategies most likely would demand that prescription rates be about 10 times higher.
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PMID:The antisuicidal and mortality-reducing effect of lithium prophylaxis: consequences for guidelines in clinical psychiatry. 1297 Oct 12

Lithium is a potent noncompetitive inhibitor of inositol monophosphatases, enzymes involved in phosphoinositide (PI) and inositol phosphate metabolism. A critical component of the PI pathway is phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P(2)), which is hydrolyzed to second messengers and has a direct role in synaptic vesicle function. Interestingly, a number of genes involved in the synthesis and dephosphorylation of PtdIns(4,5)P(2) are found in regions of the genome previously mapped in bipolar disorder (BD) including 10p12, 21q22, and 22q11, among others. Some of these regions overlap with loci mapped in schizophrenia (SZ). One gene involved in PI metabolism that maps to a region of interest is 10p12-linked PIP5K2A, a member of the phosphatidylinositol 4-phosphate 5-kinase family. Polymorphism screening revealed the existence of an imperfect CT repeat polymorphism located near the exon 9-intron 9 splice donor site. A modest difference was found in the distribution of alleles from this highly polymorphic variant when bipolar and schizophrenic subjects were compared with controls; relatively rare short repeat variants were found more commonly in patients and homozygosity for a common long repeat variant was found more commonly in controls. These data suggest that the imperfect CT repeat in PIP5K2A intron 9 should be further investigated as a possible candidate allele for 10p12-linked psychiatric disorders.
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PMID:Polymorphism screening of PIP5K2A: a candidate gene for chromosome 10p-linked psychiatric disorders. 1458 45

Globally, a million people commit suicide every year, and 10-20 million attempt it. Mood disorders, especially major depressive disorder (MDD) and bipolar disorder, are the most common psychiatric conditions associated with suicide. Primary (psychiatric and physical illness), secondary (psychosocial), and tertiary (demographic) risk factors for suicide have been identified. Comorbid psychiatric illness, particularly anxiety symptoms or disorders, significantly increase the risk of suicidal behavior. Current standard risk assessments and precautions may be of limited value, while assessing the severity of anxiety and agitation may be more effective in identifying patients at risk. Lithium is the medication that has most consistently demonstrated an antisuicidal effect. The effects of antidepressants and conventional antipsychotics on suicide risk are uncertain, but atypical antipsychotics appear promising. Atypical antipsychotics have beneficial effects on depressed mood both in patients with MDD and in patients with bipolar disorder. In addition, data in patients with schizophrenia have demonstrated a significant improvement in the incidence of suicidal behavior with clozapine compared with olanzapine. Electroconvulsive therapy appears to have an acute benefit on suicidality.
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PMID:Atypical antipsychotics and suicide in mood and anxiety disorders. 1470 12

Cerebral excitability is normally distributed, and pubertal age is a distinguishing factor. The final developmental event in CNS comprising selective pruning of excitatory synapses coincides with puberty. With early puberty, excess excitation and synaptic density, we have photic susceptibility, paroxysmal EEGs, disturbed circadian rhythms, paroxysmal disorders treated with drugs lowering excitation. Manic-depressive psychosis accords with this. Migraine with paroxysmal EEG, photophobia, hemianopsia, scintillating scotomas, excess excitation in the visual system, benefits from lowering excitation. With late puberty, attenuated CNS, we have disorders in need of raising excitation to avoid breakdown of circuitry, insufficient fill-in mechanism, silent spots, subjectively experienced only--objectively verifiable psychosis: i.e., schizophrenia treated with convulsant neuroleptics. By affecting pubertal age, we affect the distribution of excitation and of post-pubertal brain disorders in accordance with their level of excitation. Excitation is equally important in chronic disorders: l'dopa adversity in Parkinsonism could be due to further lowering of excitation in patients with a deficiency, a schizophrenia-like psychosis develops. Given unavoidable adversity of anti-psychotics, and a marked rise in suicide in schizophrenic and manic-depressive since their introduction, we want to prevent the occurrence of disorders at the extremes, whether very early or late puberty. DHA normalises excitability at all levels of excitation. An adequate daily intake of DHA, before puberty as well as after, might probably reduce or eliminate a development of psychopathology. Lithium is a robust neurotropic agent, and lithiation of the drinking water could be a way of reducing suicide, homicide, violent behaviour, and drug abuse.
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PMID:A "new-old" way of thinking about brain disorder, cerebral excitability--the fundamental property of nervous tissue. 1553 32

The objective of this study was to assess the pharmacokinetics of the antipsychotic aripiprazole when coadministered with lithium or valproate. Two open-label, sequential treatment design studies were conducted in chronically institutionalized patients with schizophrenia or schizoaffective disorder requiring treatment with lithium (n = 12) or valproate (divalproex sodium) (n = 10). Patients received aripiprazole 30 mg/day on days 1 to 14 and aripiprazole with concomitant therapy on days 15 to 36. Lithium was titrated from 900 mg until serum concentrations reached 1.0 to 1.4 mEq/L for at least 5 days. Valproate was titrated to 50 to 125 mg/L. Coadministration with lithium increased mean Cmax and AUC values of aripiprazole by about 19% and 15%, respectively, whereas the apparent oral clearance decreased by 15%. There was no effect on the steady-state pharmacokinetics of the active metabolite of aripiprazole. Coadministration with valproate decreased the AUC and Cmax of aripiprazole by 24% and 26%, respectively, with minimal effects on the active metabolite. Therapeutic doses of lithium and divalproex had no clinically significant effects on the pharmacokinetics of aripiprazole in patients with schizophrenia or schizoaffective disorder.
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PMID:Pharmacokinetics of aripiprazole and concomitant lithium and valproate. 1560 9

The term 'off-label' prescribing refers to the use of a drug outside the terms of its Marketing Authorization, including prescribing for an unlicensed indication. The aims of the study were to determine the frequency of off-label prescriptions for mood stabilizers (lithium and antiepileptics) among inpatients of a large psychiatric hospital, the nature of the off-label clinical indications in use and whether patients had been informed about the off-label usage.A cross-sectional survey of inpatients aged 18-65 years at St Andrew's Hospital, Northampton, UK and interviews with consultant psychiatrists about off-label usage of mood stabilizers were carried out. Of the 249 patients studied, 75 (30.1%) were receiving one or more mood stabilizers, of which 71 (94.7%) were off-label. The most frequently cited off-label indications for mood stabilizers were: prophylaxis of mood swings (48 cases), treatment of aggression (31), manic symptoms (10), antipsychotic augmentation in treatment-resistant schizophrenia (7) and post-traumatic stress disorder (6). Lithium was prescribed infrequently. The reasons for this are discussed. Although in most instances the psychiatrist was aware the drug was being used off-label, in less than one-third of cases had the patient been informed of this, partly because of anticipated difficulties in their understanding the off-label concept, but also because of concerns that this information could adversely affect compliance. The off-label prescription of mood stabilizers is very common in psychiatry and such usage benefits patients. When prescribing off-label, psychiatrists should consider the evidence that the drug is likely to be effective for the unlicensed indication. Where there is limited evidence of benefit, a trial of the drug, with clinical monitoring, may be indicated. Patients should be fully informed about their medication, and this includes information that the prescription is off-label. Pharmacists can assist this process. The off-label concept may be difficult for some patients to understand.
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PMID:A survey of the off-label use of mood stabilizers in a large psychiatric hospital. 1598 96

Lithium has been shown to inhibit bone resorption and to interact with W nt signaling, potentially pointing to bone anabolic properties. We, therefore, studied the effects of lithium on fracture risk using a case-control study design. Cases were all subjects including children with any fracture sustained during the year 2000 (n=124,655). For each case, three controls (n=373,962) matched according to age and gender was randomly drawn from the background population. Adjustments were made for use of other psychotropic drugs (neuroleptics, antidepressants, and anxiolytics/sedatives), psychiatric disease (manic depressive states, schizophrenia, and other psychoses), and other confounders. The effect of dose was examined by stratifying for cumulated dose (DDD, defined daily dose). In the crude analysis, there was a decreasing relative risk of any fracture with increasing accumulated dose of lithium. After adjustment for psychotropic drug use, the risk of any fracture was decreased (odds ratio [OR] 0.74, 95% confidence interval [CI] 0.60--0.92 for 250--849 DDD, and OR 0.67, 95% CI 0.55--0.81 for >or= 850 DDD of lithium). For Colles' fractures and spine fractures, a significant decrease was seen with >or= 850 DDD (OR 0.57, 95% CI 0.35--0.94 for Colles' fracture and OR 0.32, 95% CI 0.11--0.95 for spine fractures). For hip fractures, a nonsignificant trend toward a decrease was seen; however, without a dose-response relationship. Adjustment for further confounders did not change the results. Lithium treatment was associated with a decreased risk of fractures potentially pointing at bone anabolic properties.
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PMID:Reduced relative risk of fractures among users of lithium. 1600 81

Dysregulated protein kinase C (PKC) distribution and activation, and abnormal receptor-G protein coupling, have been implicated in the pathophysiology of bipolar affective disorder (BD). The therapeutic effectiveness of lithium has also been correlated with its ability to reduce PKC activation and G protein-mediated signaling. We examine the cellular distribution and activation of PKC and receptor-G protein coupling in blood platelets from normal controls, patients with BD mania or schizophrenia during treatment-free state, and after lithium or valproic acid administration. PKC activity was measured under basal and 50 nM phorbol 12-myristate, 13-acetate (PMA), 1 microM serotonin or 0.5 U/ml thrombin-stimulated conditions. The coupling of G proteins to serotonin or thrombin receptors were assessed by serotonin or thrombin-mediated [35S]GTPgammaS binding to membrane Galpha proteins. The results demonstrate that membrane-associated PKC activity and stimulus-induced PKC translocation are increased in BD manic, whereas stimulus-elicited PKC translocation is attenuated in schizophrenic patients. Lithium and valproic acid treatments attenuated the stimulus-induced PKC translocations to a similar degree and decreased PKC activity in both cytosolic and membranous fractions after two weeks of drug administration. An increase in 5-HT or thrombin stimulated [35S]GTPgammaS binding to Galpha proteins was detected in BD manic but not in schizophrenic patients although basal [35S]GTPgammaS binding was not different across the diagnostic groups. Lithium and valproic acid treatments similarly reduced receptor-G protein coupling with comparable time courses. Thus, increased membrane-associated PKC, cytosol to membrane PKC translocation and receptor-G protein coupling in platelets of BD manic patients were alleviated by lithium or valproic acid treatments.
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PMID:Lithium and valproic acid treatments reduce PKC activation and receptor-G protein coupling in platelets of bipolar manic patients. 1604 35

Historically, success in the pharmacological treatment of bipolar disorder has arisen either from serendipitous findings or from studies with drugs (antipsychotics and anticonvulsants) developed for other indications (schizophrenia and epilepsy, respectively). Lithium has been in widespread clinical use in the treatment of bipolar disorder for > 30 years. Development of lithium-mimetic compounds has the potential to result in a more specific medication, with fewer side effects and a less narrow dose range. However, novel medications based upon a known mechanism of action of this drug are yet to be developed. Increasing evidence suggests that a next-generation lithium compound may derive from knowledge of a direct target of lithium, glycogen synthase kinase-3 (GSK-3). GSK-3 is an intracellular enzyme implicated as a critical component in many neuronal signalling pathways. However, despite the large body of preclinical data discussed in this review, definitive validation of GSK-3 as therapeutically relevant target of lithium will require clinical trials with novel GSK-3 inhibitors. A number of recent reports suggest that it is possible to develop selective, small-molecule GSK-3 inhibitors.
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PMID:Targeting glycogen synthase kinase-3 as an approach to develop novel mood-stabilising medications. 1670 78


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