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

Angiotensin (ANG)-containing axons, terminals, and receptors have been found in the hippocampus. When angiotensin II (ANG II) is administered to the dentate gyrus, long-term potentiation (LTP) induction, in response to medial perforant path stimulation, is inhibited and it can be blocked by losartan, an ANG II AT1 receptor antagonist. ANG II has been shown to mediate impairment of the retention of an inhibitory shock avoidance response and to be involved in ethanol and diazepam inhibition of dentate gyrus LTP, all of which can be blocked by losartan. Nicotine acetylcholine receptors are found in the hippocampus and nicotine is involved in the enhancement of complex and important psychological functions that are mediated by the hippocampus; therefore, the possibility that nicotine prevents the ANG II inhibition of dentate granule cell LTP was examined. Nicotine pretreatment reduced ANG II inhibition of LTP induction in a dose-dependent manner. Mecamylamine blocked the nicotine antagonism of ANG II-induced LTP inhibition and normal LTP occurred, whereas hexamethonium was ineffective in blocking these central effects of nicotine. Nicotine by itself did not affect normal LTP under these conditions. Nicotinic blocking of the ANG II inhibition of a frequency dependent type of synaptic plasticity provides a function for central nicotinic receptors and a possible mechanism of action a) to explain the enhancement of learning and memory by nicotine, b) an explanation for tobacco smoking while drinking alcohol, and c) a possible basis for the excessive use of tobacco in depression and schizophrenia that supports a possible therapeutic use of nicotine in some mental disorders.
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PMID:Nicotine blocks angiotensin II inhibition of LTP in the dentate gyrus. 895 46

The interrelationship between alcohol dependence and schizophrenia is very complex. On the one hand, chronic alcoholism alone can result in a chronic, schizophrenia-like psychosis (alcoholic hallucinosis) which cannot be distinguished from schizophrenia on the basis of psychopathological or clinical symptoms. On the other hand, recent clinical and epidemiological studies point at a significantly increased prevalence for substance abuse and dependence in schizophrenia, especially of alcohol. Pathophysiological mechanisms possibly involved in the onset of hallucinations in alcoholics and recent studies on the comorbidity of alcohol dependence and schizophrenia are discussed.
Alcohol Alcohol Suppl 1994
PMID:Alcohol dependence and schizophrenia: what are the interrelationships? 897 70

The case notes of all 64 referred abnormal offenders (mental patients with criminal records) sent to a psychiatric hospital between January 1971 to May 1996 were examined. It was found that severe mental disorder like schizophrenia (27 out of 64) was the most common cause of violent crimes such as homicide. Epilepsy 10.9 (n = 7) was another important neuropsychiatric condition related to violence. Alcohol and cannabis abuse were an associated factor in 21 (32.8%) referred cases. Culture bound syndromes like "Amok Syndrome" and "Spirit Possession Syndrome" were also found as a cause of violent behavior.
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PMID:Mental disorders in abnormal offenders in Papua New Guinea. 921 5

The present study evaluated smooth pursuit eye movement (SPEM) function in 36 cocaine-dependent patients, with or without a paternal history of alcoholism, and 12 nondrug-dependent normal volunteers. None of the subjects in either group met DSM-III-R diagnostic criteria for schizophrenia, or delusional, major affective, or schizotypal personality disorders. None possessed a history of seizures, significant head injury, HIV-1 infection, or regular medication use. SPEMs were elicited by a pendulum, oscillated at 0.5 Hz, and recorded using electro-oculographic techniques. Tracking accuracy was estimated by the power of the horizontal electro-oculograph at the stimulus oscillation frequency. Analyses revealed that the SPEM tracking accuracy of cocaine-dependent patients without a paternal history of alcoholism was superior to that of the normal control group. SPEM tracking in these patients correlated positively with years of cocaine and polysubstance abuse. In contrast, patients with a paternal history of alcoholism exhibited subnormal SPEM tracking performance. These differences could not be explained by other family history, demographic, or drug use variables.
Alcohol Clin Exp Res 1997 Aug
PMID:Smooth pursuit eye movement dysfunction in abstinent cocaine abusers: effects of a paternal history of alcoholism. 926 43

A series of 33 patients with combined (injurious) sleepwalking, sleep terrors, and rapid eye movement (REM) sleep behavior disorder (viz. "parasomnia overlap disorder") was gathered over an 8-year period. Patients underwent clinical and polysomnographic evaluations. Mean age was 34 +/- 14 (SD) years; mean age of parasomnia onset was 15 +/- 16 years (range 1-66); 70% (n = 23) were males. An idiopathic subgroup (n = 22) had a significantly earlier mean age of parasomnia onset (9 +/- 7 years) than a symptomatic subgroup (n = 11) (27 +/- 23 years, p = 0.002), whose parasomnia began with either of the following: neurologic disorders, n = 6 [congenital Mobius syndrome, narcolepsy, multiple sclerosis, brain tumor (and treatment), brain trauma, indeterminate disorder (exaggerated startle response/atypical cataplexy)]; nocturnal paroxysmal atrial fibrillation, n = 1; posttraumatic stress disorder/major depression, n = 1; chronic ethanol/amphetamine abuse and withdrawal, n = 1; or mixed disorders (schizophrenia, brain trauma, substance abuse), n = 2. The rate of DSM-III-R (Diagnostic and Statistical Manual, 3rd edition, revised) Axis 1 psychiatric disorders was not elevated; group scores on various psychometric tests were not elevated. Forty-five percent (n = 15) had previously received psychologic or psychiatric therapy for their parasomnia, without benefit. Treatment outcome was available for n = 20 patients; 90% (n = 18) had substantial parasomnia control with bedtime clonazepam (n = 13), alprazolam and/or carbamazepine (n = 4), or self-hypnosis (n = 1). Thus, "parasomnia overlap disorder" is a treatable condition that emerges in various clinical settings and can be understood within the context of current knowledge on parasomnias and motor control/dyscontrol during sleep.
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PMID:A parasomnia overlap disorder involving sleepwalking, sleep terrors, and REM sleep behavior disorder in 33 polysomnographically confirmed cases. 945 62

Association studies with the DRD2 Taq1A marker have been variable in implicating DRD2 as a "Reward Deficiency Syndrome Gene" for alcoholism and substance abuse. Given that the Taq1A marker is not functionally significant, second-generation studies on the DRD2 receptor to identify functional variants and evaluate their effect on the phenotype are the logical step towards confirming and extending the DRD2 hypothesis. This article discusses the implications and process of progress made in these directions. The new findings are the description of structural variants in the D2 receptor, the demonstration that one of these, Ser311Cys, largely prevents signal transduction following receptor activation and the use of Ser311Cys in a large association and sib-pair linkage anlysis in an American Indian isolate. In this particular population, the Cys311 variant is far more abundant (0.16) than in Caucasians (0.03). Genotyping of Ser311Cys, the DRD2 intron 2 STR, and the Taq1A marker in 459 subjects, including 373 sib-pairs and 15 Cys311/Cys311 homozygous individuals, revealed no association to alcoholism, substance use disorders, or schizophrenia. The implication is that a DRD2 variant that dramatically impairs receptor function was not sufficient to significantly alter alcoholism vulnerability in a relatively large and also genetically and environmentally homogeneous sample.
Alcohol 1998 Jul
PMID:A functionally deficient DRD2 variant [Ser311Cys] is not linked to alcoholism and substance abuse. 965 Jun 35

Hurst analysis of EKG data obtained from a population of alcoholic (n = 13) and nonalcoholic (n = 48) subjects was undertaken. Potential subjects (n = 120) were screened using the Schedule for Affective Disorders and Schizophrenia and Structured Clinical Interview for DSM-III instruments. Data from subjects with a diagnosis of current alcohol dependence were analyzed. Subjects with diagnoses such as major depression, bipolar disorder or schizophrenia (Axis I diagnoses), or personality disorders (Axis II diagnoses) were excluded from analysis. Subjects undergoing testing were free of alcohol and illicit drugs. Alcoholic subjects had no clinical evidence of alcohol withdrawal symptoms at the time of testing. EKG data were obtained with eyes open or with eyes closed. Approximately 3.5 min of data were obtained for each condition. Alcoholic subjects had less complex heart rate dynamics as evidenced by higher values of H = 0.18 +/- 0.05 (mean +/- SEM), compared with healthy comparison subjects with H = 0.09 +/- 0.02, p < 0.014 for the eyes closed condition, and H = 0.17 +/- 0.05 (mean +/- SEM) compared with healthy comparison subjects with H = 0.07 +/- 0.02,p < 0.011 for the eyes open condition. A gender effect was seen, with female subjects showing evidence of more complex heart rate dynamics than male subjects.
Alcohol Clin Exp Res 1999 Apr
PMID:Effects of alcohol use and gender on the dynamics of EKG time-series data. 1023 12

Alcohol and other drugs of abuse are commonly used by persons with schizophrenia and contribute to the overall morbidity of the disorder. Standard, or typical, antipsychotic drugs do not limit such substance use and may even render it more likely. However, preliminary data from our group and others suggest that the atypical antipsychotic clozapine may decrease substance use in this population. While recognizing the likelihood that substance use decreases negative symptoms (as well as extrapyramidal symptoms) in persons with schizophrenia, we hypothesize that the biological basis of substance use relates to a "reward-deficiency syndrome" secondary to dysfunctional dopamine-mediated mesocorticolimbic neurons in these individuals. We further suggest that clozapine's beneficial effect in patients with comorbid schizophrenia and substance use disorders may relate to its presumed ability to ameliorate the deficits in both the mesocortical and mesolimbic dopaminergic neuronal projections through its various actions on dopaminergic, serotonergic, and particularly noradrenergic neurons.
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PMID:Clozapine for comorbid substance use disorder and schizophrenia: do patients with schizophrenia have a reward-deficiency syndrome that can be ameliorated by clozapine? 1037 Apr 35

Multicentre trials in patients with schizophrenia confirm that olanzapine is a novel antipsychotic agent with broad efficacy, eliciting a response in both the positive and negative symptoms of schizophrenia. Compared with traditional antipsychotic agents, olanzapine causes a lower incidence of extrapyramidal symptoms and minimal perturbation of prolactin levels. Generally, olanzapine is well tolerated. The pharmacokinetics of olanzapine are linear and dose-proportional within the approved dosage range. Its mean half-life in healthy individuals was 33 hours, ranging from 21 to 54 hours. The mean apparent plasma clearance was 26 L/h, ranging from 12 to 47 L/h. Smokers and men have a higher clearance of olanzapine than women and nonsmokers. After administering [14C]olanzapine, approximately 60% of the radioactivity was excreted in urine and 30% in faeces. Olanzapine is predominantly bound to albumin (90%) and alpha 1-acid glycoprotein (77%). Olanzapine is metabolised to its 10- and 4'-N-glucuronides, 4'-N-desmethylolanzapine [cytochrome P450 (CYP) 1A2] and olanzapine N-oxide (flavin mono-oxygenase 3). Metabolism to 2-hydroxymethylolanzapine via CYP2D6 is a minor pathway. The 10-N-glucuronide is the most abundant metabolite, but formation of 4'-N-desmethylolanzapine is correlated with the clearance of olanzapine. Olanzapine does not inhibit CYP isozymes. No clinically significant metabolic interactions were found between olanzapine and diazepam, alcohol (ethanol), imipramine, R/S-warfarin, aminophylline, biperiden, lithium or fluoxetine. Fluvoxamine, an inhibitor of CYP1A2, increases plasma concentrations of olanzapine; inducers of CYP1A2, including tobacco smoke and carbamazepine, decrease olanzapine concentrations. Orthostatic changes were observed when olanzapine and diazepam or alcohol were coadministered. Pharmacodynamic interactions occurred between olanzapine and alcohol, and olanzapine and imipramine, implying that patients should avoid operating hazardous equipment or driving an automobile while experiencing the short term effects of the combinations. Individual factors with the largest impact on olanzapine pharmacokinetics are gender and smoking status. The plasma clearance of olanzapine generally varies over a 4-fold range, but the variability in the clearance and concentration of olanzapine does not appear to be associated with the severity or duration of adverse effects or the degree of efficacy. Thus, dosage adjustments appear unnecessary for these individual factors. However, dosage modification should be considered for patients characterised by a combination of factors associated with decreased oxidative metabolism, for example, debilitated or elderly women who are nonsmokers.
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PMID:Olanzapine. Pharmacokinetic and pharmacodynamic profile. 1051 17

The prevalence and demographic and clinical correlates of lifetime substance use disorders were examined in a cohort of 325 recently hospitalized psychiatric patients (53% schizophrenia or schizoaffective disorder). Alcohol use was the most common type of substance use disorder, followed by cannabis and cocaine use. Univariate analyses indicated that gender (male), age (younger), education (less), history of time in jail, conduct disorder symptoms, and antisocial personality disorder symptoms were predictive of substance use disorders. Lifetime cannabis use disorder was uniquely predicted by marital status (never married) and fewer psychiatric hospitalizations during the previous 6 months. Optimal classification tree analysis, an exploratory, nonlinear method of identifying patient subgroups, was successful in predicting 74 percent to 86 percent of the alcohol, cannabis, and cocaine use disorders. The implications of this method for identifying specific patient subgroups and service needs are discussed.
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PMID:Substance use disorder in hospitalized severely mentally ill psychiatric patients: prevalence, correlates, and subgroups. 1075 80


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