Cocaine as a risk factor for neuroleptic-induced acute dystonia

Movement disorders associated with substance use in adults living in precarious housing or homelessness

OBJECTIVE

Many individuals living in precarious housing or homelessness have multimorbid illnesses, including substance use, psychiatric, and neurological disorders. Movement disorders (MDs) associated substance use are amongst the poorly studied subtopics of drug-induced MDs. The aim of the present study was, therefore, to determine the proportion affected and severity of different signs of MDs, as well as their associations with substance use in a community-based sample of precariously housed and homeless individuals.

METHODS

Participants were recruited from an impoverished urban neighborhood and were assessed for substance dependence and self-reported substance use (alcohol, cannabis, cocaine, methamphetamine, nicotine, and opioids), as well as for the severity of signs of MDs (akathisia, dyskinesia, dystonia, and parkinsonism). Adjusted regression models were used to estimate the associations of the severity of signs with the frequency of substance use over the past 4 weeks and with the baseline diagnosis of substance dependence.

RESULTS

The proportion of the sample with clinically relevant signs of MDs in any of the four categories was 18.6% (n = 401), and these participants demonstrated lower levels of functioning than those without signs. Of the different types of substance use, only methamphetamine (its frequency of use and dependence) was significantly associated with greater severity of overall signs of MDs. Frequency of methamphetamine use significantly interacted with age and sex, whereby older female participants exhibited the greatest overall severity with increased methamphetamine use. Of the different signs of MDs, methamphetamine use frequency was positively associated with the severity of trunk/limb dyskinesia and hypokinetic parkinsonism. Relative to no use, concurrent use of antipsychotics demonstrated lower severity of trunk/limb dyskinesia and greater severity of hypokinetic parkinsonism with methamphetamine use, and greater severity of dystonia with cocaine use.

CONCLUSIONS

Our study found a high proportion of MDs in a relatively young sample, and their severity was consistently associated with methamphetamine use, moderated by participant demographics and antipsychotic use. These disabling sequelae represent an important and understudied neurological condition that may affect quality of life and will require further study.

Transient dystonia correlates with parkinsonism after 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine in nonhuman primates

Unilateral internal carotid artery 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) infusion in non-human primates produces transient contralateral hemi-dystonia followed by stable contralateral hemi-parkinsonism; the relationship between dystonia and parkinsonism remains unclear. We hypothesized that transient dystonia severity following MPTP correlates with parkinsonism severity. In male Macaca nemestrina (n = 3) and M. fascicularis (n = 17) we administered unilateral intra-carotid MPTP, then correlated validated blinded ratings of transient peak dystonia and delayed parkinsonism. We also correlated dystonia severity with post-mortem measures of residual striatal dopamine and nigral neuron counts obtained a mean 53 ± 15 days following MPTP, after resolution of dystonia but during stable parkinsonism. Median latency to dystonia onset was 1 day, and peak severity 2.5 days after MPTP; total dystonia duration was 13.5 days. Parkinsonism peaked a median of 19.5 days after MPTP, remaining nearly constant thereafter. Peak dystonia severity highly correlated with parkinsonism severity (r[18] = 0.82, p < 0.001). Residual cell counts in lesioned nigra correlated linearly with peak dystonia scores (r[18] = -0.68, p=<0.001). Dystonia was not observed in monkeys without striatal dopamine depletion (n = 2); dystonia severity correlated with striatal dopamine depletion when residual nigral cell loss was less than 50% ([11] r = -0.83, p < 0.001) but spanned a broad range with near complete striatal dopamine depletion, when nigral cell loss was greater than 50%. Our data indicate that residual striatal dopamine may not reflect dystonia severity. We speculate on mechanisms of transient dystonia followed by parkinsonism that may be studied using this particular NHP MPTP model to better understand relationships of transient dystonia to nigrostriatal injury and parkinsonism.

Application of gamma irradiation on morphological, biochemical, and molecular aspects of wheat (Triticum aestivum L.) under different seed moisture contents

Nuclear technology is currently used as a tool in mutation breeding to improve crops by increasing genetic variation. The ionization of gamma rays produces large amounts of free radicals, simulating stressors in the natural environment. To avoid gamma-ray-induced oxidative stress, plants use antioxidant defense systems. Exposure of plants to irradiation can affect the germination, growth, and production of metabolites. Plants' sensitivity to irradiation depends on genetic and environmental factors such as moisture content. For this purpose, the effects of different gamma irradiation doses [0, 100, 200, 300, and 400 Gray (Gy)] and different seed moisture contents (7, 13, and 19%) on traits such as seed germination, seedling growth, molecular and biochemical alterations in antioxidant enzymes were examined in the current study. Based on the results, the highest seed germination percentage was observed in the interaction effect of seed moisture at 13% with an irradiation dose of 400 Gy (98.89%). Seedling survival percent and seedling length decreased with increasing doses of gamma irradiation at different seed moisture contents. Increasing gamma irradiation doses were reduced root and stem fresh and dry weight, and root and stem length. The highest level of catalase enzyme activity and expression was observed at 200 and 300 Gy irradiation doses at different moisture contents. The peroxidase and polyphenol oxidase gene expression were reduced at all contents of gamma irradiation doses and seed moisture compared to the control. It can be concluded that the dose of 200-300 Gy of gamma irradiation reduced plant growth by 30% in terms of fresh and dry weight and length of plants, as well as enhanced the expression of antioxidant enzymes. The results of this study could help plant breeders select an appropriate dose rate in wheat for further research.

Neurobiological mechanisms associated with antipsychotic drug-induced dystonia

Dystonia is by far the most intrusive and invalidating extrapyramidal side effect of potent classical antipsychotic drugs. Antipsychotic drug-induced dystonia is classified in both acute and tardive forms. The incidence of drug-induced dystonia is associated with the affinity to inhibitory dopamine D2 receptors. Particularly acute dystonia can be treated with anticholinergic drugs, but the tardive form may also respond to such antimuscarinic treatment, which contrasts their effects in tardive dyskinesia. Combining knowledge of the pathophysiology of primary focal dystonia with the anatomical and pharmacological organization of the extrapyramidal system may shed some light on the mechanism of antipsychotic drug-induced dystonia. A suitable hypothesis is derived from the understanding that focal dystonia may be due to a faulty processing of somatosensory input, so leading to inappropriate execution of well-trained motor programmes. Neuroplastic alterations of the sensitivity of extrapyramidal medium-sized spiny projection neurons to stimulation, which are induced by the training of specific complex movements, lead to the sophisticated execution of these motor plans. The sudden and non-selective disinhibition of indirect pathway medium-sized spiny projection neurons by blocking dopamine D2 receptors may distort this process. Shutting down the widespread influence of tonically active giant cholinergic interneurons on all medium-sized spiny projection neurons by blocking muscarinic receptors may result in a reduction of the influence of extrapyramidal cortical-striatal-thalamic-cortical regulation. Furthermore, striatal cholinergic interneurons have an important role to play in integrating cerebellar input with the output of cerebral cortex, and are also targeted by dopaminergic nigrostriatal fibres affecting dopamine D2 receptors.

Acute onset of orofacial dystonia from promethazine treatment: A case report

RATIONALE

Promethazine is an antihistamine agent used commonly for nausea and allergy. Along with its anticholinergic and antidopaminergic functions, promethazine is also used for psychiatric symptoms, such as troubling sleep, anxiety, and agitation. Previous studies have reported that promethazine may occasionally elicit acute dystonia in some individuals, especially for young children and pregnant women.

PATIENT CONCERNS

The 68-year-old female patient was admitted to our hospital because of feeling anxious and intermittent palpitation for over 1 year. She developed acute orofacial dystonia following promethazine treatment.

DIAGNOSES

Her diagnoses was generalized anxiety disorder.

INTERVENTIONS

Discontinuation of the offending agent, promethazine, and injection of Botulinum toxin.

OUTCOMES

The acute orofacial dystonia was finally alleviated by local injection of Botulinum toxin.

LESSONS

Careful assessment of the risk of developing acute dystonia is also needed in old patients when initiating the promethazine treatment.

[Antipsychotic-induced motor symptoms in schizophrenic psychoses-Part 1 : Dystonia, akathisia und parkinsonism]

Acute antipsychotic-induced movement disorders (AIMD) are clinically relevant since they are frequently associated with high subjective distress, and since over the long-term they can negatively impact treatment adherence of patients with schizophrenic psychoses. This review article summarizes the relevant studies on the prevalence, risk factors, prevention and treatment options and instruments for early prediction of acute AIMD in schizophrenic psychoses. The current evidence and treatment recommendations are divided into three main areas: acute dystonia, akathisia, and parkinsonism. For the treatment of acute dystonia trihexyphenidyl and biperiden have shown their efficacy. Considering pharmacological treatment of akathisia, there is some preliminary evidence for medication with lipophilic beta-receptor blockers (propranolol and pindolol), clonidine, benzodiazepines, mianserin, mirtazapine und trazodone. The treatment options for drug-induced parkinsonism include reduction or switching from one antipsychotic to another with a lower affinity for dopamine D₂ receptors, amantadine or in the regular administration of anticholinergic drugs. In conclusion, acute AIMD is easily to recognize but is not always effectively and durably treated. Early recognition and treatment of acute AIMD could be associated with improved treatment outcomes.

Drug-induced movement disorders

Movement disorders are frequently a result of prescription drugs or of illicit drug use. This article focuses on prescribed drugs but briefly mentions drugs of abuse. The main emphasis is on movement disorders caused by dopamine receptor-blocking agents. However, movement disorders caused by other drugs are also briefly discussed.

Movement disorders in patients with schizophrenia and a history of substance abuse

OBJECTIVE

The movement disorders acute dystonia, akathisia, Parkinsonian symptoms and tardive dyskinesia [extrapyramidal side effects (EPSs)] are recognized adverse effects of antipsychotic medication. Previous studies have indicated that substance abuse in patients with schizophrenia can worsen EPS. This study therefore investigated the relationship between drug and alcohol use and EPS in a group of patients with schizophrenia.

METHODS

Seventy patients with schizophrenia assessed for drug and alcohol use, global functioning, EPS and suicidality. Chlorpromazine equivalents were correlated to levels of EPS and substance abuse.

RESULTS

Current EPS were found in 65% of the sample despite three-quarters of the patients receiving second-generation antipsychotics. An even higher level of patients, 87%, was found to have a history of EPS. A long history of schizophrenia independently predicted presence of any EPS, particularly akathisia, controlling for history of substance abuse which was a non-significant predictor.

CONCLUSIONS

History or current use of alcohol or drug abuse did not predict EPS, except for alcohol abuse at the time of diagnosis which was associated with current akathisia. Length of illness was correlated with EPS, whereas suicidality was not linked to akathisia. Neither chlorpromazine equivalent antipsychotic dose nor whether the patient received first-generation or second-generation antipsychotic medication was significantly associated with EPS or substance abuse.

Positron emission tomography molecular imaging of dopaminergic system in drug addiction

Dopamine (DA) is involved in drug reinforcement, but its role in drug addiction remains unclear. Positron emission tomography (PET) is the first technology used for the direct measurement of components of the dopaminergic system in the living human brain. In this article, we reviewed the major findings of PET imaging studies on the involvement of DA in drug addiction, especially in heroin addiction. Furthermore, we summarized PET radiotracers that have been used to study the role of DA in drug addiction. To investigate presynaptic function in drug addiction, PET tracers have been developed to measure DA synthesis and transport. For the investigation of postsynaptic function, several radioligands targeting dopamine one (D1) receptor and dopamine two (D2) receptor are extensively used in PET imaging studies. Moreover, we also summarized the PET imaging findings of heroin addiction studies, including heroin-induced DA increases and the reinforcement, role of DA in the long-term effects of heroin abuse, DA and vulnerability to heroin abuse and the treatment implications. PET imaging studies have corroborated the role of DA in drug addiction and increase our understanding the mechanism of drug addiction.

Extrapyramidal symptoms in substance abusers with and without schizophrenia and in nonabusing patients with schizophrenia

Extrapyramidal symptoms (EPS) such as parkinsonism, dystonia, dyskinesia, and akathisia are conditions of impaired motor function, which are associated with chronic antipsychotic treatment in schizophrenia. In addition, EPS is often exacerbated by psychoactive substance (PAS) abuse, which is frequently observed in this population. Few studies, however, have investigated the contribution of PAS abuse on EPS in PAS-abusers without comorbid psychosis. This study compared the occurrence of EPS in outpatient schizophrenia patients with (DD group; n= 36) and without PAS abuse (SCZ group; n = 41) as well as in nonschizophrenia PAS abusers undergoing detoxification [substance use disorder (SUD) group; n = 38]. Psychiatric symptoms were measured using the Positive and Negative Syndrome Scale and the Calgary Depression Scale for schizophrenia. Extrapyramidal symptoms were evaluated with the Extrapyramidal Symptoms Rating Scale and the Barnes Akathisia Scale. SUD diagnoses were complemented with urine drug screenings. We found that DD patients exhibited significantly more parkinsonism than SCZ patients. Our subanalyses revealed that cocaine and alcohol abuse/dependence was responsible for the increase in parkinsonism in DD patients. Additionally, we found that SUD individuals exhibited significantly more akathisia than SCZ patients. In these latter individuals, subanalyses revealed that alcohol and cannabis abuse/dependence was responsible for the increase in akathisia. Our results suggest that PAS abuse is a contributor to EPS in individuals with and without schizophrenia.

Mood stabilizers in the treatment of substance use disorders

Individuals suffering from drug addiction may also manifest features of bipolar spectrum disorders. Hyperthymic and cyclothymic temperaments may render individuals vulnerable to later development of substance abuse. Bipolar disorders themselves may be altered or precipitated by substance use, most notably by stimulants (amphetamines), alcohol, and cannabinoids. The clinical usefulness of mood stabilizers, particularly antiepileptics, has been established as safe and effective in substance abusers with and without comorbid mood disorders. Most studies on this issue have been of short duration and focused on the resolution of a currently manifest period of illness. Few studies have been conducted on the usefulness of these drugs on the long-term longitudinal course of these diseases, such as frequently encountered recurrent relapses into states of agitation, impulsivity, and/or dissatisfaction. As opposed to the clinical experience with traditional antidepressants and neuroleptics, antiepileptics do not induce counter-polar states (depressed patients abruptly turning manic or hypomanic; nor patients currently hypomanic or manic turning abruptly depressed). Many clinicians consider antiepileptic mood stabilizers to be the preferred category of medications for the treatment of such patients. Valproate appears to be a potentially fruitful medication to study in these dual diagnosis patients due to preliminary evidence demonstrating its anticraving efficacy.

Lower level of endogenous dopamine in patients with cocaine dependence: findings from PET imaging of D(2)/D(3) receptors following acute dopamine depletion

OBJECTIVE

Previous positron emission tomography (PET) imaging studies have demonstrated that cocaine dependence is associated with a decrease in dopamine type 2 and 3 (D(2)/D(3)) receptor binding in cocaine-dependent individuals relative to healthy comparison subjects. However, given the nature of PET imaging, it is possible that the measured decrease in radiotracer binding results from an increase in baseline dopamine levels. The purpose of this study was to measure D(2)/D(3) receptors following acute dopamine depletion in cocaine-dependent volunteers relative to healthy comparison subjects.

METHOD

Cocaine-dependent volunteers (N=15) and healthy matched comparison subjects (N=15) were scanned using PET, with the dopamine receptor radiotracer [(11)C]raclopride, at baseline and again following acute depletion of endogenous dopamine via alpha-methyl-para-tyrosine (AMPT) administration. Changes in radiotracer binding were measured in the subdivisions of the striatum (caudate, putamen, and ventral striatum) in addition to the striatum as a whole.

RESULTS

Findings revealed that cocaine-dependent volunteers exhibited lower levels of endogenous dopamine relative to comparison subjects, which was measured as an increase in [(11)C]raclopride binding following AMPT administration. The increase in [(11)C]raclopride binding in the striatum was 11.1% (SD=4.4%) in healthy comparison subjects and 5.7% (SD=5.9%) in cocaine-dependent volunteers. Similar differences were seen in the subdivisions of the striatum.

CONCLUSIONS

The decrease in striatal D(2)/D(3 )receptors associated with cocaine dependence cannot be attributed to higher levels of endogenous dopamine.

Substance abuse is associated with increased extrapyramidal symptoms in schizophrenia: a meta-analysis

BACKGROUND

Psychoactive substances (PAS) may interact with antipsychotics in the development of extrapyramidal symptoms (EPS) in schizophrenia. PAS exert acute and chronic impacts on the basal ganglia. Clinical data have been gathered about the effects of PAS on EPS in schizophrenia, producing inconsistent results. This meta-analysis sought to determine whether PAS enhance EPS in schizophrenia patients.

METHODS

A search of the literature using computerized engines was undertaken. Studies were retained in the analysis if: (i) they included schizophrenia patients with and without substance abuse; and (ii) they comprised a measure of EPS using valid instruments.

RESULTS

Sixteen studies available were identified, involving 3479 patients. The composite analysis revealed a small and positive effect size (g=0.260), suggesting increased EPS in substance-abusing patients. Cocaine was associated with the largest effect size estimate (g=0.613). Dual diagnosis patients were more frequently males than single diagnosis patients. Thus, we performed a sub-analysis of studies with no confounders (e.g. age, sex and/or symptoms). The pooling of these 10 studies produced a moderate and positive effect size (g=0.401).

DISCUSSION

Our results show that PAS negatively impact on EPS in schizophrenia, especially when potential confounding factors are controlled. Cocaine emerged as the PAS with the most deleterious effects on EPS in schizophrenia. Our results have implications for the prevention of EPS in schizophrenia and for the design of future studies on the topic.

Methamphetamine psychosis in which tardive dystonia was successfully treated with clonazepam

Reported herein is a case of methamphetamine psychosis in which tardive dystonia was treated successfully with clonazepam. The patient was a 69-year-old man who had taken methamphetamine habitually for approximately 40 years. Auditory hallucinations had developed 25 years previously, for which haloperidol had been prescribed. Tardive dystonia had developed in December 2005. Haloperidol was withdrawn and risperidone or olanzapine alone had been administered, but neither had improved the dystonic posture. However, when clonazepam was added, a gradual improvement in the dystonic posture became evident. Tardive dystonia is currently treated on a trial-and-error basis. Accumulation of further cases similar to the present one is very important for establishing an effective treatment.

Cocaine use as a risk factor for ziprasidone-induced acute dystonia

Cocaine use is an under-recognized risk factor of antipsychotic-induced acute dystonia. A case of a patient with psychotic illness and concurrent cocaine use developing acute dystonia with ziprasidone is described.

Increased extrapyramidal symptoms in patients with schizophrenia and a comorbid substance use disorder

Few data have been gathered about the impact of psychoactive substances on extrapyramidal symptoms (EPS) in schizophrenia, and so far, inconsistent results have been reported. We studied 41 outpatients with schizophrenia (based on DSM-IV criteria), who were divided into two groups: with (n = 17) and without (n = 24) a substance use disorder (alcohol, cannabis, and/or cocaine). Both groups were matched for sociodemographic data and psychiatric symptoms (Positive and Negative Syndrome Scale). EPS were evaluated with the Extrapyramidal Symptoms Rating Scale and the Barnes Akathisia Scale, and all patients were stable on either quetiapine or clozapine. Patients receiving anticholinergic drugs were excluded. Analyses of variance were conducted on both groups and showed that schizophrenia patients with a comorbid substance use disorder (especially cocaine) displayed more EPS compared with non-abusing patients.

The expert consensus guideline series. Treatment of behavioral emergencies 2005

OBJECTIVES

Due to inherent dangers and barriers to research in emergency settings, few data are available to guide clinicians about how best to manage behavioral emergencies. Key constructs such as agitation are poorly defined. This lack of empirical data led us to undertake a survey of expert opinion, results of which were published in the 2001 Expert Consensus Guidelines on the Treatment of Behavioral Emergencies. Several second-generation (atypical) antipsychotics (SGAs) are now available in new formulations for treating behavioral emergencies (e.g., intramuscular [i.m.] olanzapine and ziprasidone; rapidly dissolving tablets of olanzapine and risperidone). Critical questions face the field. The SGAs are significantly different from the FGAs and from each other and have not been studied in unselected patients as were the FGAs. Can the SGAs can be thought of as a class, do all antipsychotics have similar anti-agitation effects in different conditions, and, if equally effective, what limits might their safety profiles impose? Should antipsychotics be used more specifically to treat psychotic conditions, while benzodiazepines (BNZs) alone are used nonspecifically? Few data are available concerning combinations of SGAs and BNZs, and findings concerning the traditional combination of haloperidol plus a BNZ may not be relevant to combinations with SGAs. The culture is also evolving with more emphasis on patient involvement in treatment decisions. An international consensus has been developing that calming rather than sedation is the appropriate endpoint of behavioral emergency interventions. We undertook a new survey of expert opinion to update recommendations from the earlier survey.

METHOD

A written survey of 61 questions (1,020 options) was mailed to 50 experts in the field, 48 (96%) of whom completed it. The survey sought to define level of agitation at which emergency interventions are appropriate, scope of assessment depending on urgency and patients' ability to cooperate, guiding principles for selecting interventions, and appropriate physical and medication strategies at different levels of diagnostic confidence for a variety of provisional diagnoses and complicating conditions. A modified version of the RAND Corporation's 9-point scale for rating appropriateness of medical decisions was used to score most options. Consensus was defined as a non-random distribution of scores by chi-square "goodness-of-fit" test. We assigned a categorical rank (first line/preferred, second line/alternate, third line/usually inappropriate) to each option based on the 95% confidence interval around the mean. Ratings were used to develop guidelines for preferred strategies in key clinical situations. This study received financial support from multiple sponsors, with the panel kept blind to sponsorship to reduce possible bias. Medication ratings were based on responses of only those respondents with direct experience with each drug. In reporting practice patterns, the panel was asked to respond based on actual data rather than estimates.

RESULTS

The expert panel reached consensus on 78% of the options rated on the 9-point scale. The responses suggest that physicians can make provisional diagnoses with some confidence and that pharmacological and nonpharmacological interventions are selected differentially based on diagnosis and other salient demographic and medical features. BNZs are recommended when no data are available, when there is no specific treatment (e.g., personality disorder), or when they may have specific benefits (e.g., intoxication). No single SGA emerges as a nonspecific replacement for haloperidol; instead, different SGAs are preferred in various circumstances consistent with current evidence. To the degree that haloperidol is recommended, it is almost always in combination with a BNZ; haloperidol alone is preferred only in the medically compromised. In contrast, the SGAs are more often recommended for use alone, and the panel would avoid combining BNZs with some SGAs. Oral risperidone alone or combined with a BNZ receives strong support in a variety of situations. Oral olanzapine was rated very similarly to risperidone, with slightly higher ratings than risperidone in situations where it has been studied (e.g., schizophrenia, mania) and slightly lower ratings where it has not been studied or safety may be a concern; there was less support for combining oral olanzapine with a BNZ. For oral treatment of agitation related to schizophrenia or mania, olanzapine alone, risperidone alone or combined with a BNZ, and haloperidol plus a BNZ are first line, with strong support also for combining divalproex with the antipsychotic for presumed mania. Oral ziprasidone and quetiapine generally received similar second-line ratings in most situations. If a parenteral agent is needed, i.m. olanzapine alone received somewhat more support than i.m. ziprasidone alone; however, there was more support for i.m. ziprasidone alone or combined with a BNZ than for i.m. olanzapine plus a BNZ, probably reflecting safety concerns. For example, for a provisional diagnosis of schizophrenia, first-line parenteral options are i.m. olanzapine or ziprasidone alone or i.m. haloperidol or ziprasidone combined with a BNZ. Neither of the new parenteral formulations received as much support as traditional agents (i.m. BNZs, i.m. haloperidol) when no data are available or the diagnosis involves medical comorbidity or intoxication. When initial intervention with risperidone, ziprasidone, or haloperidol is unsuccessful, the panel recommended adding a BZD to the antipsychotic. However, when initial treatment with olanzapine or quetiapine is unsuccessful, increasing the dosage is recommended. Perphenazine was consistently rated second line and droperidol and chlorpromazine received third-line ratings throughout.

CONCLUSIONS

Within the limits of expert opinion and with the expectation that future research data will take precedence, these guidelines suggest that the SGAs are now preferred for agitation in the setting of primary psychiatric illnesses but that BNZs are preferred in other situations.

Dopamine in drug abuse and addiction: results from imaging studies and treatment implications

The involvement of dopamine in drug reinforcement is well recognized but its role in drug addiction is much less clear. Imaging studies have shown that the reinforcing effects of drugs of abuse in humans are contingent upon large and fast increases in dopamine that mimic but exceed in the intensity and duration those induced by dopamine cell firing to environmental events. In addition, imaging studies have also documented a role of dopamine in motivation, which appears to be encoded both by fast as well as smooth DA increases. Since dopamine cells fire in response to salient stimuli, the supraphysiological activation by drugs is likely to be experienced as highly salient (driving attention, arousal conditioned learning and motivation) and may also reset the thresholds required for environmental events to activate dopamine cells. Indeed, imaging studies have shown that in drug-addicted subjects, dopamine function is markedly disrupted (decreases in dopamine release and in dopamine D2 receptors in striatum) and this is associated with reduced activity of the orbitofrontal cortex (neuroanatomical region involved with salience attribution and motivation and implicated in compulsive behaviors) and the cingulate gyrus (neuroanatomical region involved with inhibitory control and attention and implicated in impulsivity). However, when addicted subjects are exposed to drug-related stimuli, these hypoactive regions become hyperactive in proportion to the expressed desire for the drug. We postulate that decreased dopamine function in addicted subjects results in decreased sensitivity to nondrug-related stimuli (including natural reinforcers) and disrupts frontal inhibition, both of which contribute to compulsive drug intake and impaired inhibitory control. These findings suggest new strategies for pharmacological and behavioral treatments, which focus on enhancing DA function and restoring brain circuits disrupted by chronic drug use to help motivate the addicted subject in activities that provide alternative sources of reinforcement, counteract conditioned responses, enhance their ability to control their drive to take drugs and interfere with their compulsive administration.

The addicted human brain viewed in the light of imaging studies: brain circuits and treatment strategies

Imaging studies have provided evidence of how the human brain changes as an individual becomes addicted. Here, we integrate the findings from imaging studies to propose a model of drug addiction. The process of addiction is initiated in part by the fast and high increases in DA induced by drugs of abuse. We hypothesize that this supraphysiological effect of drugs trigger a series of adaptations in neuronal circuits involved in saliency/reward, motivation/drive, memory/conditioning, and control/disinhibition, resulting in an enhanced (and long lasting) saliency value for the drug and its associated cues at the expense of decreased sensitivity for salient events of everyday life (including natural reinforcers). Although acute drug intake increases DA neurotransmission, chronic drug consumption results in a marked decrease in DA activity, associated with, among others, dysregulation of the orbitofrontal cortex (region involved with salience attribution) and cingulate gyrus (region involved with inhibitory control). The ensuing increase in motivational drive for the drug, strengthened by conditioned responses and the decrease in inhibitory control favors emergence of compulsive drug taking. This view of how drugs of abuse affect the brain suggests strategies for intervention, which might include: (a) those that will decrease the reward value of the drug of choice; (b) interventions to increase the saliency value of non-drug reinforcers; (c) approaches to weaken conditioned drug behaviors; and (d) methods to strengthen frontal inhibitory and executive control. Though this model focuses mostly on findings from PET studies of the brain DA system it is evident that other neurotransmitters are involved and that a better understanding of their roles in addiction would expand the options for therapeutic targets.

Treatment of behavioral emergencies: a summary of the expert consensus guidelines

OBJECTIVES

Behavioral emergencies are a common and serious problem for consumers, their communities, and the healthcare settings on which they rely, but there is little research to guide provider responses to this challenge. Key constructs such as agitation have not been adequately operationalized so that the criteria defining a behavioral emergency are vague. A significant number of deaths of patients in restraint has focused government and regulators on these issues, but a consensus about key elements in the management of behavioral emergencies has not yet been articulated by the provider community. The authors assembled a panel of 50 experts to define the following elements: the threshold for emergency interventions, the scope of assessment for varying levels of urgency and cooperation, guiding principles in selecting interventions, and appropriate physical and medication strategies at different levels of diagnostic confidence and for a variety of etiologies and complicating conditions.

METHOD

A written survey with 808 decision points was completed by 50 experts. A modified version of the RAND Corporation 9-point scale for rating appropriateness of medical decisions was used to score options. Consensus on each option was defined as a non-random distribution of scores by chi-square "goodness-of-fit" test. We assigned a categorical rank (first line/preferred choice, second line/ alternate choice, third line/usually inappropriate) to each option based on the 95% confidence interval around the mean rating. Guideline tables were constructed describing the preferred strategies in key clinical situations.

RESULTS

The expert panel reached consensus on 83% of the options. The relative appropriateness of emergency interventions was ascertained for a continuum of behaviors. When asked about the frequency with which emergency interventions (parenteral medication, restraint, seclusion) were required in their services, 47% of the experts reported that such interventions were necessary for 1%-5% of patients seen in their services and 32% for 6%-20%. In general, the consensus of this panel lends support to many elements of recent regulations from the Health Care Financing Administration (now the Centers for Medicare and Medicaid Services), including the timing of clinician assessment and reassessment and the intensity of nursing care. However, the panel did not endorse the concept of "chemical restraint," instead favoring the idea that medications are treatments for target behaviors in behavioral emergencies even when the causes of these behaviors are not well understood. Control of aggressive behavior emerged as the highest priority during the emergency; however, preserving the physician-patient relationship was rated a close second and became the top priority in the long term. Oral medications, particularly concentrates, were clearly preferred if it is possible to use them. Benzodiazepines alone were top rated in 6 of 12 situations. High-potency conventional antipsychotics used alone never received higher ratings than benzodiazepines used alone. A combination of a benzodiazepine and an antipsychotic was preferred for patients with suspected schizophrenia, mania, or psychotic depression. There was equal support for high-potency conventional or atypical antipsychotics (particularly liquids) in oral combinations with benzodiazepines. Droperidol emerged in fourth place in some situations requiring an injection.

CONCLUSIONS

To evaluate many of the treatment options in this survey, the experts had to extrapolate beyond controlled data. Within the limits of expert opinion and with the expectation that future research data will take precedence, these guidelines provide some direction for addressing common clinical dilemmas in the management of psychiatric emergencies and can be used to inform clinicians in acute care settings regarding the relative merits of various strategies.

Correlation between neuroleptic binding to sigma(1) and sigma(2) receptors and acute dystonic reactions

Acute dystonic reactions are motor side effects that occur soon after the initiation of neuroleptic treatment. Although earlier studies indicate that these abnormal movements can be induced in animals and humans via activation of sigma receptors, the relative contribution of the different sigma receptor subtypes is unknown. Since sigma(1) and sigma(2) receptor are differentially represented in motor regions of the brain, the affinities of 17 neuroleptics for these sigma receptor subtypes were determined using competition binding studies. The results revealed that most neuroleptics do not exhibit selectivity for either of the sigma receptor subtypes, as reflected by a significant correlation between the affinities of the neuroleptics for sigma(1) vs. sigma(2) receptors. Moreover, when the sigma binding affinities of the neuroleptics were correlated with the tendency of the drugs to produce acute dystonic reactions in humans, there was a significant correlation for both subtypes. Together with earlier studies in animals, the data suggest that neuroleptic-induced motor side effects can be mediated through both sigma(1) and sigma(2) receptors.