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)

The authors examined whether smoking while wearing a transdermal nicotine patch over 32 h was well-tolerated and led to smoking suppression in heavy smokers with schizophrenia. In a crossover design, 10 male veteran smokers with schizophrenia were admitted for two brief inpatient stays to smoke while wearing a transdermal nicotine or placebo patch. Carbon monoxide in expired air, self-reported cigarettes per day, nicotine plasma levels, and psychiatric ratings were measured. Nicotine levels increased during active patch treatment, without evidence of nicotine toxicity. Psychiatric symptoms, carbon monoxide and cigarettes per day did not change, although eight subjects had a decrease in expired carbon monoxide on the active patch. Dyskinesias showed a small, but significant, increase during smoking plus active patch. The heaviest smokers (identified by placebo phase nicotine plasma level or CO level above group median; n = 5) had a statistically significant decrease in expired carbon monoxide of at least 20%. Smoking while wearing the nicotine patch over 32 h was well tolerated. Significant decreases in carbon monoxide smoking indices were seen for the heaviest smokers. These findings suggest further investigation of a smoking reduction intervention in this population.
Nicotine Tob Res 1999 Mar
PMID:Acute feasibility and safety of a smoking reduction strategy for smokers with schizophrenia. 1107 88

The neurobiology of nicotine addiction is reviewed within the context of neurobiological and behavioral theories postulated for other drugs of abuse. The roles of various neurotransmitter systems, including acetylcholine, dopamine, serotonin, glutamate, gamma-aminobutyric acid, and opioid peptides in acute nicotine reinforcement and withdrawal from chronic administration are examined followed by a discussion of potential neuroadaptations within these neurochemical systems that may lead to the development of nicotine dependence. The link between nicotine administration, depression and schizophrenia are also discussed. Finally, a theoretical model of the neurobiological mechanisms underlying acute nicotine withdrawal and protracted abstinence involves alterations within dopaminergic, serotonergic, and stress systems that are hypothesized to contribute to the negative affective state associated with nicotine abstinence.
Nicotine Tob Res 2000 Feb
PMID:Neural mechanisms underlying nicotine addiction: acute positive reinforcement and withdrawal. 1107 38

Previous work from this laboratory had demonstrated the presence of endogenous morphine, strychnine and nicotine in the mammalian brain and human serum samples. Morphine is synthesised from tyrosine and strychnine and nicotine from tryptophan. This study examines the role of strychnine, nicotine and morphine in neuropsychiatric disorders. The blood levels of tyrosine, tryptophan, strychnine, nicotine and morphine were studied as also RBC membrane Na(+)-K+ ATPase activity. It was found that serum tyrosine levels were reduced and tryptophan levels elevated in all neuropsychiatric disorders studied with a reduction in RBC Na(+)-K+ ATPase activity. Nicotine was present in significant amounts in serum of patients with schizophrenia, CNS glioma and syndrome X with multiple lacunar state. Morphine was present in significant amounts only in the serum of patients with multiple sclerosis and MDP. Strychnine was present in significant amounts in the serum of patients with epilepsy, Parkinson's disease and MDP. The presence of nicotine and strychnine in significant amounts could be related to elevated tryptophan levels suggesting the synthesis of these alkaloids from tryptophan. Morphine was not detected in most of the disorders owing to low tyrosine levels noted in them. Na(+)-K+ ATPase inhibition noticed in most of the disorders could be related to decreased hyperpolarising morphinergic transmission and increased depolarising nicotinergic and strychinergic transmission. The role of morphine, strychnine and nicotine in the pathogenesis of these disorders in the setting of membrane Na(+)-K+ ATPase inhibition is discussed.
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PMID:Endogenous strychnine, nicotine, and morphine--description of hypo and hyper-strychninergic, nicotinergic and morphinergic state in relation to neuropsychiatric diseases. 1111 26

Nicotine acetylcholine receptors (nAChRs) are implicated in the pathogenesis of schizophrenia because the prevalence of smoking among schizophrenic patients is extraordinarily high, and nicotine has been demonstrated to improve some psychophysiological dysfunction in schizophrenics. In addition, recent studies have suggested linkage of the alpha(7) nAChR gene region in families of schizophrenics. In a population-based association study, we tested the hypothesis that the allelic variant, with a 2-bp deletion, of the human alpha(7) nAChR gene confers susceptibility to schizophrenic disorders. We genotyped alpha(7) nAChR in 146 patients with schizophrenic disorders and 151 controls. The results showed no significant difference in genotype or allele frequencies between schizophrenic patients and control subjects. This suggests that alpha(7) nAChR 2-bp deletion plays no major role in the pathogenesis of schizophrenic disorders. Other nAChR variants in schizophrenic disorders may need further investigation.
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PMID:Association study of a nicotinic receptor variant with schizophrenic disorders. 1115 Aug 93

Genetic and biological data have suggested a role for the neuronal nicotinic acetylcholine receptors in the neuropathophysiology of schizophrenia. Studies in human postmortem brain demonstrate dose-dependent increases in nicotinic receptor binding in normal smokers. We found this upregulation to be reduced in schizophrenic smokers, many of whom had taken typical neuroleptics during their lifetime. The present study examined the hypothesis that typical antipsychotic drug treatment might modulate nicotinic receptor upregulation in a rat model. Nicotine, administered alone or in combination with haloperidol, increased both high and low affinity neuronal nicotinic receptors in a region specific manner. Haloperidol had no generalized effect on basal levels of nicotinic receptor binding or nicotine induced upregulation of nicotinic receptors. However, haloperidol attenuated high affinity nicotinic receptor upregulation in thalamus and low affinity receptor upregulation in hippocampus. These results suggest that haloperidol is not likely to affect nicotinic receptor regulation by smoking in most brain regions.
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PMID:The effect of nicotine and haloperidol co-treatment on nicotinic receptor levels in the rat brain. 1116 78

Nicotine and other nicotinic agonists have been found to improve performance on attention and memory tasks. Clinical studies using nicotine skin patches have demonstrated the efficacy of nicotine in treating cognitive impairments associated with Alzheimer's disease, schizophrenia, and attention-deficit/hyperactivity disorder. Experimental animal studies have demonstrated the persistence of nicotine-induced working memory improvement with chronic exposure, in addition to the efficacy of a variety of nicotinic agonists. Mechanistic studies have found that alpha7 and alpha4beta2 nicotinic receptors in the hippocampus are critical for nicotinic involvement in cognitive function. Clinical and experimental animal studies provide mutually supporting information for the development of novel nicotinic therapies for cognitive dysfunction.
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PMID:Cognitive effects of nicotine. 1123 Aug 77

The purpose of this study was to investigate the effect of adding sustained-release (SR) bupropion to cognitive behavioral therapy (CBT) on smoking behavior and stability of psychiatric symptoms in patients with schizophrenia. We conducted a 3-month, double-blind, placebo-controlled trial of bupropion SR, 150 mg/day, added to a concurrent CBT program with 3-month follow-up in 19 stable outpatients with schizophrenia who wanted to quit smoking. Eighteen subjects completed the trial. Bupropion treatment was associated with significantly greater reduction in smoking, as measured by self-report verified by expired-air carbon monoxide (6/9 subjects, 66%), than placebo (1/9 subjects, 11%) during the 3-month active treatment period and the 3-month follow-up period. One subject in the bupropion group (11%) and no subjects in the placebo group achieved sustained tobacco abstinence for the 6-month trial. Bupropion treatment was associated with improvement in negative symptoms and greater stability of psychotic and depressive symptoms, compared with placebo, during the quit attempt. Subjects in the bupropion group experienced significant weight loss, compared with those on placebo during the smoking cessation attempt. These data suggest that bupropion SR, 150 mg/day, combined with CBT, may facilitate smoking reduction in patients with schizophrenia while stabilizing psychiatric symptoms during a quit attempt.
Nicotine Tob Res 2001 Nov
PMID:A pilot trial of bupropion added to cognitive behavioral therapy for smoking cessation in schizophrenia. 1169 8

Schizophrenic patients have impairments in cognitive function, including deficits in visuospatial working memory (VSWM). VSWM is mediated, in part, by prefrontal cortical dopamine (DA) function, and dysregulation of prefrontal cortical DA systems may contribute to the pathophysiology of schizophrenia. Nicotine has complex effects on spatial working memory (SWM) in animal studies, with most studies demonstrating enhancement of SWM. Cigarette smoking is highly prevalent in schizophrenia, and these patients may smoke cigarettes to remediate cognitive deficits. The present study examined the effects of acute (<1 week) and prolonged (8-10 weeks) smoking abstinence on VSWM in schizophrenic (n = 23) and control (n = 29) nicotine-dependent cigarette smokers during placebo-controlled smoking cessation trials. Schizophrenic and control smoking patients had significant impairments in VSWM compared to non-smoking controls, after adjusting for differences in age, education and depressive symptoms. Schizophrenic smokers who quit smoking had further impairments in VSWM, and control quitters had improvements in VSWM. Abstinence-induced changes in VSWM varied as a function of gender in controls, but not in schizophrenics. These changes in VSWM appeared to be independent of study medications, and smoking abstinence did not significantly alter performance on the Stroop Color Word Test in either group. These results suggest that smoking abstinence differentially alters VSWM in schizophrenic vs. control smokers, and that cigarette smoking has beneficial effects on VSWM in schizophrenic, but not control, smokers.
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PMID:Effects of smoking abstinence on visuospatial working memory function in schizophrenia. 1246 65

Patients with mental illness have a higher incidence of smoking than the general population and are the major consumers of tobacco products. This population includes subjects with schizophrenia, manic depression, depression, posttraumatic stress disorder (PTSD), attention-deficit disorder (ADD), and several other less common diseases. Smoking cessation treatment in this group of patients is difficult, often leading to profound depression. Several recent findings suggest that increased smoking in the mentally ill may have an underlying biological etiology. The mental illness schizophrenia has been most thoroughly studied in this regard. Nicotine administration normalizes several sensory-processing deficits seen in this disease. Animal models of sensory deficits have been used to identify specific nicotinic receptor subunits that are involved in these brain pathways, indicating that the alpha 7 nicotinic receptor subunit may play a role. Genetic linkage in schizophrenic families also supports a role for the alpha 7 subunit with linkage at the alpha 7 locus on chromosome 15. Bipolar disorder has some phenotypes in common with schizophrenia and also exhibits genetic linkage to the alpha 7 locus, suggesting that these two disorders may share a gene defect. The alpha 7 receptor is decreased in expression in schizophrenia. [(3)H]-Nicotine binding studies in postmortem brain indicate that high-affinity nicotinic receptors may also be affected in schizophrenia.
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PMID:Smoking and mental illness. 1179 54

The increased rate of smoking in schizophrenia patients remains unexplained and may reflect attempts at self-treatment. The effect sought from smoking may be related to nicotine's stimulating action. We tested this hypothesis by examining the relationship between smoking status and finger tapping rate, a measure of central processing, in schizophrenia patients treated with atypical antipsychotics. Smokers showed significantly faster finger tapping rates than non-smokers. This was not related to clinical state, illness chronicity, medication side-effects, antipsychotic dose or plasma concentrations. Nicotine can improve central processing in medicated schizophrenia patients and this may constitute part of the incentive for smoking.
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PMID:Schizophrenic patients who smoke have a faster finger tapping rate than non-smokers. 1187 31


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