Cigarette smoking is associated with abnormal involuntary movements in the general male population--a study of men born in 1933

Does the degree of smoking effect the severity of tardive dyskinesia? A longitudinal clinical trial

Background

Tardive dyskinesia (TD) is a movement disorder observed after chronic neuroleptic treatment. Smoking is presumed to increase the prevalence of TD. The question of a cause-effect-relationship between smoking and TD, however, remains to be answered. Purpose of this study was to examine the correlation between the degree of smoking and the severity of TD with respect to differences caused by medication.

Method

We examined 60 patients suffering from schizophrenia and TD. We compared a clozapine-treated group with a group treated with typical neuroleptics. Movement disorders were assessed using the Abnormal-Involuntary-Movement-Scale and the technical device digital image processing, providing rater independent information on perioral movements.

Results

We found a strong correlation (.80 < r < .90, always p < .0001) between the degree of smoking and severity of TD. Repeated measurements revealed a positive correlation between changes in cigarette consumption and changes of the severity of TD (p < .0001). Analyses of covariance indicated a significant group-effect with a lower severity of TD in the clozapine-group compared to the typical-neuroleptics-group (p = .010). Interaction-analyses indicated a higher impact of smoking on the severity of TD in the typical-neuroleptics-group compared to the clozapine-group (p = .033).

Conclusion

Concerning a possible cause-effect-relationship between smoking and TD, smoking is more of a general health hazard than neuroleptic exposure in terms of TD.

Potential Therapeutic Application for Nicotinic Receptor Drugs in Movement Disorders

Emerging studies indicate that striatal cholinergic interneurons play an important role in synaptic plasticity and motor control under normal physiological conditions, while their disruption may lead to movement disorders. Here we discuss the involvement of the cholinergic system in motor dysfunction, with a focus on the role of the nicotinic cholinergic system in Parkinson's disease and drug-induced dyskinesias. Evidence for a role for the striatal nicotinic cholinergic system stems from studies showing that administration of nicotine or nicotinic receptor drugs protects against nigrostriatal degeneration and decreases L-dopa-induced dyskinesias. In addition, nicotinic receptor drugs may ameliorate tardive dyskinesia, Tourette's syndrome and ataxia, although further study is required to understand their full potential in the treatment of these disorders. A role for the striatal muscarinic cholinergic system in movement disorders stems from studies showing that muscarinic receptor drugs acutely improve Parkinson's disease motor symptoms, and may reduce dyskinesias and dystonia. Selective stimulation or lesioning of striatal cholinergic interneurons suggests they are primary players in this regulation, although multiple central nervous systems appear to be involved.

IMPLICATIONS

Accumulating data from preclinical studies and clinical trials suggest that drugs targeting CNS cholinergic systems may be useful for symptomatic treatment of movement disorders. Nicotinic cholinergic drugs, including nicotine and selective nAChR receptor agonists, reduce L-dopa-induced dyskinesias, as well as antipsychotic-induced tardive dyskinesia, and may be useful in Tourette's syndrome and ataxia. Subtype selective muscarinic cholinergic drugs may also provide effective therapies for Parkinson's disease, dyskinesias and dystonia. Continued studies/trials will help address this important issue.

Cigarette smoking and schizophrenia

It has been recognised for many years that patients with psychiatric illnesses, especially schizophrenia, smoke to excess. However, recently there has been a resurgence of interest in the high prevalence of nicotine addiction in patients with schizophrenia. It has become increasingly clear that heavy cigarette smoking is intimately associated with the schizophrenic illness and that this may have implications for the underlying neurobiology of schizophrenia.

Necessity of oral health intervention in schizophrenic patients - A review

Individuals with mental illness often cannot perform day to day activities due to a psychiatric or emotional disorder. Schizophrenia is one such psychiatric disorder characterized by worsening self-care ability with progressing mental illness. This disease may potentially deteriorate oral health by affecting the subject's ability to perform oral hygiene measures. Literature on oral disease manifestations in schizophrenia is limited. Lack of desire for oral health care as well as generally poor awareness of oral health issues in these patients, compounded further by side effects of medications, may complicate dental management in schizophrenic patients. The present review explores clinical features and possible factors associated with oral health status among those with Schizophrenia.

Antipsychotic-induced Tardive dyskinesia: from biological basis to clinical management

INTRODUCTION

Tardive dyskinesia (TD) is a chronic and disabling movement disorder with a complex pathophysiological basis. A significant percentage of patients does not receive correct diagnosis, resulting in delayed or inaccurate treatment and poor outcome. Therefore, there is a critical need for prompt recognition, implementation of efficacious treatment regimens and long-term follow up of patients with TD. Areas covered: The current paper provides an overview of emerging data concerning proposed pathophysiology theories, epidemiology, risk factors, and therapeutic strategies for TD. Expert commentary: Despite considerable research efforts, TD remains a challenge in the treatment of psychosis as the available strategies remain sub-optimal. The best scenario will always be the prophylaxis or prevention of TD, which entails limiting the use of antipsychotics.

Tardive Dyskinesia: A Historical Perspective

The goal of this column is to provide historical context on tardive dyskinesia (TD) to help the reader understand how the concept was studied and evolved over time. Psychiatrists today should understand this history and consider it in combination with more recent data on the neurobiology of TD, including data from animal studies. This combination of classic data with modern science can help readers develop a more complete understanding and lead to a more judicious use of the term TD, after consideration of all of the alternative causes of abnormal movements, including spontaneous dyskinesia (SD). We advocate that clinicians use the term SD when in doubt about the cause of a movement disorder in a given patient, as TD is never distinguishable from SD in a given patient but is instead an issue of a statistical odds ratio.

Determining Whether a Definitive Causal Relationship Exists Between Aripiprazole and Tardive Dyskinesia and/or Dystonia in Patients With Major Depressive Disorder: Part 1

This series of columns has 2 main goals: (1) to explain the use of class warnings by the US Food and Drug Administration and (2) to increase clinicians' awareness of movement disorders that may occur in patients being treated with antipsychotic medications and why it is appropriate and good practice to refrain from immediately assuming the diagnosis is tardive dyskinesia/dystonia (TD). This first column in the series will focus on the second goal, which will then serve as a case example for the first goal. Clinicians should refrain from jumping to a diagnosis of TD because a host of other causes need to be ruled out first before inferring iatrogenic causation. The causal relationship between chronic treatment with dopamine antagonists and TD is based on pharmacoepidemiology (ie, the prevalence of such movement disorders is higher in individuals receiving chronic treatment with such agents than in a control group). There is nothing pathognomonic about movement disorders, nor is there any test that can currently prove a drug caused a movement disorder in a specific individual. Another goal of this series is to describe the types of research that would be needed to establish whether a specific agent has a meaningful risk of causing TD. In this first column of the series, we present the case of a patient who developed orofacial dyskinesia while being treated with aripiprazole. In this case, the movement disorder was prematurely called TD, which led to a malpractice lawsuit. This case highlights a number of key questions clinicians are likely to encounter in day-to-day practice. We then review data concerning the historical background, incidence, prevalence, and risk factors for 2 movement disorders, TD and spontaneous dyskinesia. Subsequent columns in this series will review: (1) unique aspects of the psychopharmacology of aripiprazole, (2) the limited and inconsistent data in the literature concerning the causal relationship between aripiprazole and TD, (3) the use of class warnings by the US Food and Drug Administration, which are automatically applied to a drug if it belongs to a specific therapeutic or pharmacological class unless the manufacturer provides convincing data that it does not warrant such a class label, and (4) the types of prohibitively expensive studies that would be needed to determine whether a meaningful causal relationship between aripiprazole and TD exists.

Role for the nicotinic cholinergic system in movement disorders; therapeutic implications

A large body of evidence using experimental animal models shows that the nicotinic cholinergic system is involved in the control of movement under physiological conditions. This work raised the question whether dysregulation of this system may contribute to motor dysfunction and whether drugs targeting nicotinic acetylcholine receptors (nAChRs) may be of therapeutic benefit in movement disorders. Accumulating preclinical studies now show that drugs acting at nAChRs improve drug-induced dyskinesias. The general nAChR agonist nicotine, as well as several nAChR agonists (varenicline, ABT-089 and ABT-894), reduces l-dopa-induced abnormal involuntary movements or dyskinesias up to 60% in parkinsonian nonhuman primates and rodents. These dyskinesias are potentially debilitating abnormal involuntary movements that arise as a complication of l-dopa therapy for Parkinson's disease. In addition, nicotine and varenicline decrease antipsychotic-induced abnormal involuntary movements in rodent models of tardive dyskinesia. Antipsychotic-induced dyskinesias frequently arise as a side effect of chronic drug treatment for schizophrenia, psychosis and other psychiatric disorders. Preclinical and clinical studies also show that the nAChR agonist varenicline improves balance and coordination in various ataxias. Lastly, nicotine has been reported to attenuate the dyskinetic symptoms of Tourette's disorder. Several nAChR subtypes appear to be involved in these beneficial effects of nicotine and nAChR drugs including α4β2*, α6β2* and α7 nAChRs (the asterisk indicates the possible presence of other subunits in the receptor). Overall, the above findings, coupled with nicotine's neuroprotective effects, suggest that nAChR drugs have potential for future drug development for movement disorders.

Tardive and spontaneous dyskinesia incidence in the general population

BACKGROUND

To identify the incidence rate of spontaneous dyskinesia (SD) and tardive dyskinesia (TD) in a general population and to examine the association between dykinesia and potential risk factors (exposure to metoclopramide [MCP], antipsychotic drugs, and history of diabetes and psychoses).

METHODS

A retrospective cohort study was conducted for the years 2001 through 2010, based on medical claims data from the Deseret Mutual Benefit Administrators (DMBA).

RESULTS

Thirty-four cases of TD and 229 cases of SD were identified. The incidence rate of TD among persons previously prescribed an antipsychotic or metoclopramide (MCP) (per 1,000) was 4.6 (1.6-7.7) for those with antipsychotic drug use only, 8.5 (4.8-12.2) for those with MCP use only, and 15.0 (2.0-28.1) for those with both antipsychotic and MCP use. In the general population, the incidence rate (per 100,000 person-years) of TD was 4.3 and of probable SD was 28.7. The incidence rates of TD and SD increased with age and were greater for females. Those with diabetes or psychoses had almost a 3-fold greater risk of TD than those without either of these diseases. Persons with schizophrenia had 31.2 times increased risk of TD than those without the disease. Positive associations also existed between the selected diseases and the incidence rate of probable SD, with persons with schizophrenia having 4.4 times greater risk of SD than those without the disease.

CONCLUSIONS

SD and TD are rare in this general population. Diabetes, psychoses, and especially schizophrenia are positively associated with SD and TD. A higher proportion of those with SD present with spasm of the eyelid muscles (blepharospasm) compared more with the TD cases who present more with orofacial muscular problems.

Nicotine reduces antipsychotic-induced orofacial dyskinesia in rats

Antipsychotics are an important class of drugs for the management of schizophrenia and other psychotic disorders. They act by blocking dopamine receptors; however, because these receptors are present throughout the brain, prolonged antipsychotic use also leads to serious side effects. These include tardive dyskinesia, repetitive abnormal involuntary movements of the face and limbs for which there is little treatment. In this study, we investigated whether nicotine administration could reduce tardive dyskinesia because nicotine attenuates other drug-induced abnormal movements. We used a well established model of tardive dyskinesia in which rats injected with the commonly used antipsychotic haloperidol develop vacuous chewing movements (VCMs) that resemble human orofacial dyskinesias. Rats were first administered nicotine (minipump; 2 mg/kg per day). Two weeks later, they were given haloperidol (1 mg/kg s.c.) once daily. Nicotine treatment reduced haloperidol-induced VCMs by ∼20% after 5 weeks, with a significant ∼60% decline after 13 weeks. There was no worsening of haloperidol-induced catalepsy. To understand the molecular basis for this improvement, we measured the striatal dopamine transporter and nicotinic acetylcholine receptors (nAChRs). Both haloperidol and nicotine treatment decreased the transporter and α6β2* nAChRs (the asterisk indicates the possible presence of other nicotinic subunits in the receptor complex) when given alone, with no further decline with combined drug treatment. By contrast, nicotine alone increased, while haloperidol reduced α4β2* nAChRs in both vehicle and haloperidol-treated rats. These data suggest that molecular mechanisms other than those directly linked to the transporter and nAChRs underlie the nicotine-mediated improvement in haloperidol-induced VCMs in rats. The present results are the first to suggest that nicotine may be useful for improving the tardive dyskinesia associated with antipsychotic use.

Smoking and tardive dyskinesia in male patients with chronic schizophrenia

Interactions between smoking and movement disorders include the contrasting associations of more cigarette smoking with reductions in Parkinson's disease and increases in tardive dyskinesia (TD) symptoms. Here we examine the relationship between smoking and TD in a large sample of inpatients with schizophrenia. We used cross-sectional naturalistic methods to analyze the prevalence and severity of neuroleptic-induced TD in relation to cigarette smoking among 764 male chronic and medicated inpatients meeting DSM-IV criteria for schizophrenia. We administered a detailed questionnaire including general information, medical and psychological conditions, and smoking behaviors. We evaluated TD severity using the abnormal involuntary movement scale (AIMS) and psychopathology using the Positive and Negative Syndrome Scale (PANSS). The main statistical analyses used cross-tabulations for the prevalence of TD by smoking and multivariate regression analyses for continuous measures (AIMS and PANSS). We found that the prevalence of TD did not significantly differ between smokers (41%=237/578) and non-smokers (37%=69/186). Secondary outcomes showed a significant association between the AIMS total score and age, duration of illness and hospitalization times. Thus, smoking was not associated with TD in male Chinese schizophrenics, but consistent with previous reports, older patients with a longer duration of illness and more hospitalizations showed greater severity of TD.

Gender differences in the prevalence, risk and clinical correlates of tardive dyskinesia in Chinese schizophrenia

OBJECTIVE

Despite extensive use of antipsychotic drug treatment, few studies address the prevalence of tardive dyskinesia (TD) in homogeneous ethnic groups such as the Chinese. This study examined gender-specific relationships between TD and symptom levels in schizophrenia among Han Chinese, which have previously received little systematic study.

MATERIALS AND METHODS

Five hundred and twenty-two inpatients with schizophrenia receiving long-term treatment with antipsychotics were evaluated with the AIMS. The patient's psychopathology was assessed with the Positive and Negative Syndrome Scale (PANSS). Demographic and clinical data were collected from a detailed questionnaire and medical records.

RESULTS

The overall TD prevalence was 33.7% with rates of 39.2% (138/352) in males and 22.4% (38/170) in females (chi (2) = 14.6, df = 1, p < 0.0001; adjust odds ratio 2.06; CI, 1.32-3.16). The AIMS score in patients with TD was lower in females than males (5.3 +/- 3.9 vs 6.7 +/- 3.7, t = 2.52, p < 0.01) after adjustment for the significant covariates. TD was associated with the negative symptoms on the PANSS in both genders, and with age, PANSS total and positive symptoms in men, not women.

CONCLUSION

Our present findings suggest that there are gender differences in the prevalence, risk, and clinical correlates of TD in schizophrenia. Although this study is limited by cross-sectional designs, the magnitude of these gender-specific differences is substantial and deservers further prospective study.

[Tobacco and schizophrenia: therapeutic aspects]

Although patients with have low motivations to quit smoking, smoking cessation treatment can be effective for these patients. Patients schizophrenia who achieve significant smoking reduction during a treatment intervention can at least maintain that level of reduction at 2 years. Cigarette smoking by patients with frequently goes unaddressed, contributing to excess mortality in this population. Behavioural interventions improve smoking cessation in schizophrenia patients. Nicotine replacement can substantially reduce withdrawal symptoms. Bupropion enhances smoking abstinence rates. Bupropion is well-tolerated and safe for use in schizophrenia patients: bupropion does not worsen clinical symptoms of schizophrenia. Atypical antipsychotics may reduce smoking consumption in schizophrenia patients, in particular clozapine. Atypical antipsychotic medication, in combination with the nicotine transdermal patch, significantly enhance the rate of smoking cessation. Interactions between smoking and antipsychotic medication - Smoking increases the metabolism of the antipsychotic medications by inducing the cytochrome P450 1A2 isoform. Smoking lowers the blood levels of typical or atypical antipsychotic medication, in particular haloperidol, chlorpromazine, olanzapine and clozapine. -Abstinence can increase many psychotropics' blood levels. Accordingly, smoking appears to reduce neuroleptic-induced parkinsonism. In contrast, smoking is a risk factor for tardive dyskinesia, independent of neuroleptic exposure.

Prevalence of tobacco use in individuals with severe mental illnesses, São Paulo, Brazil

OBJECTIVE: To analyze the prevalence of cigarette smoking in individuals with severe mental illnesses in a large urban centre of a middle income country. METHODS: Cross-sectional study carried out in São Paulo. The sample (N=192) comprised individuals diagnosed with severe mental illnesses who had contact with public psychiatric care services from September to November 1997 and were aged between 18 and 65 years. Prevalence of daily tobacco smoking in the 12 months previous to the interview and characteristics associated were studied. RESULTS: Out of 192 subjects with severe mental illnesses interviewed, 115 (59.9%; 95% CI: 52.6%; 66.9%) reported smoking cigarettes on a daily basis. Male gender, marital status separated or widowed, irregular use of neuroleptic drugs and history of ten or more psychiatric admissions were independently associated with cigarette smoking. CONCLUSIONS: The prevalence of cigarette smoking in the present sample was higher than that found in the general Brazilian population. Mental care services should implement non-smoking policies and mental health providers need to help patients with severe mental illness who want to quit smoking.

Does smoking reduce akathisia? Testing a narrow version of the self-medication hypothesis

BACKGROUND

The self-medication hypothesis proposes that schizophrenia patients smoke to decrease their schizophrenia symptoms or antipsychotic side effects, but they usually start smoking before their illness and heavy smoking is not consistently associated with fewer symptoms or side effects. A narrow version of the self-medication hypothesis, heavy smoking reduces akathisia, is explored.

METHOD

The sample included 250 outpatients with DSM-IV schizophrenia assessed with the Positive and Negative Syndrome Scale (PANSS) and the Barnes Akathisia Scale. Prevalences were 69% (173/250) for smoking, 39% (98/250) for heavy smoking (> or =30 cigarettes/day), 7% (17/250) for akathisia (Barnes Global score>1), 14% (35/250) for a broader akathisia definition (Barnes Global score>0) and 20% for excited symptoms (>1 on the PANSS factor score).

RESULTS

Heavy smoking was not associated with akathisia (41% of patients with akathisia were heavy smokers versus 39% of patients without akathisia; chi2=0.3, df=1, p=0.86), even after correcting for confounding factors and/or using a broader akathisia definition. Heavy smoking was associated with excited schizophrenia symptoms (possibly reflecting agitation). Particularly in patients taking lower doses of typical antipsychotics, excited symptoms, with or without akathisia, were strongly associated with heavy smoking and appear to interact with patients' reports of smoking's calming effect as the main reason for smoking.

CONCLUSION

The self-medication hypothesis does not explain increased smoking and heavy smoking in schizophrenia. Moreover, heavy smoking may be associated with more disturbed brain homeostatic mechanisms. Prospective studies need to explore whether temporary increases in cigarette smoking may be associated with periods of higher agitation, with or without akathisia.

Nicotine use in schizophrenia: the self medication hypotheses

The behavioural and cognitive effects of nicotine in schizophrenia have received much interest in recent years. The rate of smoking in patients with schizophrenia is estimated to be two- to four-fold the rate seen in the general population. Furthermore such patients favour stronger cigarettes and may also extract more nicotine from their cigarettes than other smokers. The question has been raised whether the widespread smoking behaviour seen in this patient group is in fact a manifestation of a common underlying physiology, and that these patients smoke in an attempt to self-medicate. We present an overview of the explanations for elevated rates of smoking in schizophrenia, with particular emphasis on the theories relating this behaviour to sensory gating and cognitive deficits in this disorder that have been viewed as major support for the self-medication hypotheses.

Prevalence of and risk factors for tardive dyskinesia in a Xhosa population in the Eastern Cape of South Africa

OBJECTIVE

Despite prolonged use of antipsychotic drug treatment, the prevalence of tardive dyskinesia (TD) in a Xhosa population has not been evaluated. This study was undertaken to assess the prevalence and identify possible factors, including antioxidant intake and smoking history, which may increase or reduce the risk of TD.

METHOD

One hundred two subjects who had been exposed to typical antipsychotic drugs for at least 6 months and were currently on an antipsychotic were screened for abnormal movements using the Abnormal Involuntary Movement Scale (AIMS) rating scale. Data about current and past antipsychotic therapy, diagnoses, smoking history, and dietary factors were gathered from the patient and from chart view.

RESULT

Twenty-eight and four-tenths percent of subjects met criteria for tardive dyskinesia. Years of treatment and total cumulative antipsychotic dose were significant predictors of TD. Subjects with higher total consumption of foods containing antioxidants had lower rates of TD, but only consumption of onions was significantly associated with reduced prevalence. TD was less prevalent in smokers, but this difference did not reach statistical significance. Age, sex, and psychiatric diagnosis did not predict presence of TD.

CONCLUSION

The result of this study indicate that TD in this population is more prevalent than previously believed within this local clinical context. Prolonged treatment and total antipsychotic drug exposure are important risk factors for TD in this population. Further study of the role of concurrent medications and dietary factors is indicated.

Motivational interviewing with personalized feedback: a brief intervention for motivating smokers with schizophrenia to seek treatment for tobacco dependence

Individuals with schizophrenia have a much higher prevalence of tobacco smoking, a lower cessation rate, and a higher incidence of tobacco-related diseases than the general population. The initial challenge has been to motivate these individuals to quit smoking. This study tested whether motivational interviewing is effective in motivating smokers with schizophrenia or schizoaffective disorder to seek tobacco dependence treatment. Participants (N = 78) were randomly assigned to receive a 1-session motivational interviewing (MI) intervention, standard psychoeducational counseling, or advice only. As hypothesized, a greater proportion of participants receiving the MI intervention contacted a tobacco dependence treatment provider (32%, 11%, and 0%, respectively) and attended the 1st session of counseling (28%, 9%. and 0%) by the 1-month follow-up as compared with those receiving comparison interventions.

Does nicotine affect D2 receptor upregulation? A case-control study

OBJECTIVE

Nicotine has a powerful preventive effect on neuroleptic-induced dopamine D2 receptor upregulation in the rat. The aim of this human positron emission tomography (PET) study was to compare upregulation in a smoker and a non-smoker, both of whom had received haloperidol for the same duration of time.

METHOD

Two subjects who had been treated for 16 years with a constant dose of haloperidol were scanned after temporary haloperidol withdrawal, using [11C]-raclopride.

RESULTS

The non-smoker, who had received a dose of 10 mg/day, showed a D2 upregulation of 98% and developed severe and persistent symptoms of tardive dyskinesia (TD) upon withdrawal. The chronic smoker, who had been treated with 40 mg/day, displayed a D2 upregulation of 71% and did not develop TD.

CONCLUSION

These human observations agree with animal data which showed that nicotine can decrease neuroleptic-induced D2 receptor upregulation. This property of nicotine may play a protective role in movement disorders whose pathophysiology involves D2 receptor hypersensitivity.

Spontaneous dyskinesia in first-degree relatives of chronically ill, never-treated people with schizophrenia

BACKGROUND

We have suggested recently that there may be a subgroup of schizophrenia, namely schizophrenia with dyskinesia and striatal pathology. Might movement disorders be more common in relatives of those with schizophrenia and dyskinesia than in relatives of those without dyskinesia? Aims To determine the prevalence of abnormal movements in first-degree relatives of people with schizophrenia who themselves do or do not have abnormal movements.

METHOD

Chronically ill, never-treated people with schizophrenia in south India (n=70) and their first-degree relatives (n=181) were examined for dyskinesia using the Abnormal Involuntary Movements Scale (AIMS) and for parkinsonism by the Simpson and Angus scale.

RESULTS

Of all relatives, 25 (14%) had dyskinetic movements in at least one body area and 6 (3%) had parkinsonism. Siblings of people with schizophrenia and dyskinesia, compared with siblings of people without dyskinesia, had a higher total AIMS score and more had mild dyskinetic movements in at least one area (5/15 v. 3/34, P=0.04). There were no between-group differences in parkinsonism.

CONCLUSIONS

Dyskinesia but not parkinsonism is more common in siblings of people with schizophrenia who have the corresponding movement disorder.

Muscarinic and nicotinic cholinergic mechanisms in the mesostriatal dopamine systems

The striatum and its dense dopaminergic innervation originating in the midbrain, primarily from the substantia nigra pars compacta and the ventral tegmental area, compose the mesostriatal dopamine (DA) systems. The nigrostriatal system is involved mainly in motor coordination and in disorders such as Tourette's syndrome, Huntington's disease, and Parkinson's disease. The dopaminergic projections from the ventral tegmental area to the striatum participate more in the processes that shape behaviors leading to reward, and addictive drugs act upon this mesolimbic system. The midbrain DA areas receive cholinergic innervation from the pedunculopontine tegmentum and the laterodorsal pontine tegmentum, whereas the striatum receives dense cholinergic innervation from local interneurons. The various neurons of the mesostriatal systems express multiple types of muscarinic and nicotinic acetylcholine receptors as well as DA receptors. Especially in the striatum, the dense mingling of dopaminergic and cholinergic constituents enables potent interactions. Evidence indicates that cholinergic and dopaminergic systems work together to produce the coordinated functioning of the striatum. Loss of that cooperative activity contributes to the dysfunction underlying Parkinson's disease.

Cigarette smoking and the incidence of Parkinson's disease in two prospective studies

An inverse association between cigarette smoking and idiopathic Parkinson's disease has been reported in several retrospective studies, but prospective evidence is available only for men. We assessed the association between the incidence of Parkinson's disease and smoking in two large prospective cohort studies comprising men and women. New cases of Parkinson's disease were identified in the Nurses' Health Study for 1976-1996, and in the Health Professionals Follow-up Study for 1986-1996. Smoking history was assessed at baseline and updated on subsequent biennial questionnaires. In women, the age-adjusted rate ratios (95% confidence intervals) for Parkinson's disease relative to never-smokers were 0.7 (0.5, 1.0) for past smokers, and 0.4 (0.2, 0.7) for current smokers. In men, the age-adjusted rate ratios for Parkinson's disease relative to never-smokers were 0.5 (0.4, 0.7) for past smokers, and 0.3 (0.1, 0.8) for current smokers. In both cohorts, the strength of the association decreased with time since quitting (among past smokers), increased with number of cigarettes per day (among current smokers), and increased with pack-years of smoking. These prospective findings confirm that an inverse association between smoking and the incidence of Parkinson's disease exists in both men and women.

Smoking in patients receiving psychotropic medications: a pharmacokinetic perspective

Many psychiatric patients smoke, and are believed to be heavier smokers than those without psychiatric disorders. Cigarette smoking is one of the environmental factors that contributes to interindividual variations in response to an administered drug. Polycyclic aromatic hydrocarbons (PAHs) present in cigarette smoke induce hepatic aryl hydrocarbon hydroxylases, thereby increasing metabolic clearance of drugs that are substrates for these enzymes. PAHs have been shown to induce 3 hepatic cytochrome P450 (CYP) isozymes, primarily CYP1A1, 1A2 and 2E1. Drug therapy can also be affected pharmacodynamically by nicotine. The most common effect of smoking on drug disposition in humans is an increase in biotransformation rate, consistent with induction of drug-metabolising enzymes. Induction of hepatic enzymes has been shown to increase the metabolism and to decrease the plasma concentrations of imipramine, clomipramine, fluvoxamine and trazodone. The effect of smoking on the plasma concentrations of amitriptyline and nortriptyline is variable. Amfebutamone (bupropion) does not appear to be affected by cigarette smoking. Smoking is associated with increased clearance of tiotixene, fluphenazine, haloperidol and olanzapine. Plasma concentrations of chlorpromazine and clozapine are reduced by cigarette smoking. Clinically, reduced drowsiness in smokers receiving chlorpromazine, and benzodiazepines, compared with nonsmokers has been reported. Increased clearance of the benzodiazepines alprazolam, lorazepam, oxazepam, diazepam and demethyl-diazepam is found in cigarette smokers, whereas chlordiazepoxide does not appear to be affected by smoking. Carbamazepine appears to be minimally affected by cigarette smoke, perhaps because hepatic enzymes are already stimulated by its own autoinductive properties. Cigarette smoking can affect the pharmacokinetic and pharmacodynamic properties of many psychotropic drugs. Clinicians should consider smoking as an important factor in the disposition of these drugs.

A functional polymorphism of the cytochrome P450 1A2 (CYP1A2) gene: association with tardive dyskinesia in schizophrenia

Tardive dyskinesia (TD) is a common and potentially irreversible side effect associated with long-term treatment with typical antipsychotics. Approximately, 80% or more of patients with schizophrenia are smokers. Smoking is a potent inducer of the CYP1A2 enzyme, and is known to cause a significant decrease in plasma concentrations of some antipsychotics. Therefore, person-to-person differences in the extent of CYP1A2 induction by smoking may contribute to risk for the development of TD. Recently, a (C-->A) genetic polymorphism in the first intron of the CYP1A2 gene was found to be associated with variation in CYP1A2 inducibility in healthy volunteer smokers. The aim of this study was to test the clinical importance of the (C-->A) polymorphism in CYP1A2 in relation to TD severity. A total of 85 patients with schizophrenia were assessed for TD severity using the Abnormal Involuntary Movement Scale (AIMS), and were subsequently genotyped for the (C-->A) polymorphism in CYP1A2. The mean AIMS score in patients with the (C/C) genotype (associated with reduced CYP1A2 inducibility) was 2.7- and 3.4-fold greater than in those with the (A/C) or (A/A) genotype, respectively (F[2,82] = 7.4, P = 0.0007). Further, a subanalysis in the 44 known smokers in our sample, revealed a more pronounced effect. The means AIMS score in smokers was 5.4- and 4. 7-fold greater in (C/C) homozygotes when compared to heterozygotes and (A/A) homozygotes, respectively (F[2,41] = 3.7, P = 0.008). These data suggest that the (C-->A) genetic polymorphism in the CYP1A2 gene may serve as a genetic risk factor for the development of TD in patients with schizophrenia. Further studies in independent samples are warranted to evaluate the applicability of our findings to the general patient population receiving antipsychotic medications.

The current status of tardive dyskinesia

OBJECTIVE

This paper aims to provide an overview of the current knowledge on neuroleptic-induced tardive dyskinesia (TD) in relation to its clinical features, risk factors, pathophysiology and management.

METHOD

The published literature was selectively reviewed and assessed.

RESULTS

Tardive diskinesia is a common neurological side-effect of neuroleptic medication, the cumulative incidence of which increases with increasing duration of treatment. Its clinical manifestations are diverse and subsyndromes have been described. Many risk factors for TD are now recognised, but increasing age remains pre-eminent as a risk factor. The pathophysiology of TD is not completely understood. Of the neurotransmitter hypotheses, the dopamine receptor supersensitivity hypothesis and the gamma-aminobutyric acid insufficiency hypothesis are the main contenders. There is increasing recognition that TD may in fact be caused by neuroleptic-induced neuronal toxicity through free radical and excitotoxic mechanisms. The occurrence of spontaneous dyskinesias in schizophrenic patients and even healthy subjects suggests that neuroleptics act on a substratum of vulnerability to dyskinesia. As no effective treatment for TD is available, the primary emphasis is on prevention. Many drugs can be tried to reduce symptoms in established cases. The increasing use of atypical neuroleptics has raised the possibility of a lower incidence of TD in the future.

CONCLUSIONS

After four decades of clinical recognition, the pathophysiology of TD is still not understood and no effective treatment is available. Its prevention with the optimal usage of currently available drugs and regular monitoring of patients on long-term neuroleptic treatment remain the best strategies to reduce its impact.

Smoking among male psychiatric outpatients in Saudi Arabia

BACKGROUND

The prevalence rate of smoking among psychiatric patients has been shown to be higher than that among the general population, and this may have several neuropsychiatric implications. This cross-sectional study examines the prevalence, sociodemographic variables and pattern of smoking among psychiatric outpatients in Saudi Arabia.

PATIENTS AND METHODS

Over a period of 18 months (January 1996 to June 1997), 505 outpatients from five different hospitals were randomly selected to participate in the study.

RESULTS

It was observed that 292 patients (57.83%) were current smokers, 199 (39.4%) were nonsmokers and 14 patients (2.77%) were ex-smokers. Besides revealing certain attitudes towards smoking and religious antismoking notions, it was observed that unemployment, low education status, rural background, and drug abuse were significantly associated with smoking.

CONCLUSION

The prevalence rate of smoking revealed in this study is consistent with international data, and probably has implications similar to those reported in other studies. This study also found certain patterns of tobacco use in psychiatric outpatients characterized by certain sociodemographic variables and drug abuse.

Smoking habits, current symptoms, and premorbid characteristics of schizophrenic patients in Nithsdale, Scotland

OBJECTIVE

Previous studies of smoking habits of schizophrenic patients have found rates as high as 88%. The authors report the smoking habits of all known schizophrenic patients within a discrete geographical area and compare them with the smoking habits of a general population sample.

METHOD

All known schizophrenic patients in Nithsdale in South-West Scotland (N = 168) were invited to complete a questionnaire on smoking habits. Also assessed were mental state, drug-related side effects, and premorbid childhood personality and social adjustment.

RESULTS

One hundred thirty-five of the 168 patients returned the questionnaires. The rate of smoking among the patients was 58% (N = 78), compared with 28% in the general population. Sixty-eight percent of the patients who smoked (N = 53) had 25 or more cigarettes per day. The mean age at starting smoking was 17 years in both patients and normal subjects. Ninety percent of the patients who smoked (N = 70) started smoking before the onset of schizophrenia. Patients who smoked were younger than nonsmokers, and more of them were male. They had had more hospitalizations, and more were in contact with psychiatric services. More were receiving intramuscular antipsychotic medication. Smokers had poorer childhood social adjustment. Among the female patients, there was a positive correlation between age at starting smoking and age at onset of schizophrenia.

CONCLUSIONS

The rate of smoking and level of nicotine addiction are greater in schizophrenic patients than in the general population. Smoking may be a marker for the neurodevelopmental form of the illness and may be another environmental risk factor for schizophrenia in vulnerable individuals.